CSE2-archive/src/Backends/Rendering/OpenGL3.cpp

1090 lines
34 KiB
C++

// Released under the MIT licence.
// See LICENCE.txt for details.
// Dual OpenGL 3.2 and OpenGL ES 2.0 renderer
#include "../Rendering.h"
#include <stddef.h>
#include <stdlib.h>
#include <string.h>
#ifdef USE_OPENGLES2
#include <GLES2/gl2.h>
#else
#include <glad/glad.h>
#endif
#include "../Misc.h"
#include "Window/OpenGL.h"
#define MIN(a,b) ((a) < (b) ? (a) : (b))
#define MAX(a,b) ((a) > (b) ? (a) : (b))
#define ATTRIBUTE_INPUT_VERTEX_COORDINATES 1
#define ATTRIBUTE_INPUT_TEXTURE_COORDINATES 2
typedef enum RenderMode
{
MODE_BLANK,
MODE_DRAW_SURFACE,
MODE_DRAW_SURFACE_WITH_TRANSPARENCY,
MODE_COLOUR_FILL,
MODE_DRAW_GLYPH
} RenderMode;
typedef struct RenderBackend_Surface
{
GLuint texture_id;
size_t width;
size_t height;
} RenderBackend_Surface;
typedef struct RenderBackend_GlyphAtlas
{
GLuint texture_id;
size_t width;
size_t height;
} RenderBackend_GlyphAtlas;
typedef struct Coordinate2D
{
GLfloat x;
GLfloat y;
} Coordinate2D;
typedef struct Vertex
{
Coordinate2D position;
Coordinate2D texture;
} Vertex;
typedef struct VertexBufferSlot
{
Vertex vertices[2][3];
} VertexBufferSlot;
static struct
{
GLuint id;
struct
{
GLint vertex_transform;
GLint texture_coordinate_transform;
} uniforms;
} program_texture;
static struct
{
GLuint id;
struct
{
GLint vertex_transform;
GLint texture_coordinate_transform;
} uniforms;
} program_texture_colour_key;
static struct
{
GLuint id;
struct
{
GLint vertex_transform;
GLint colour;
} uniforms;
} program_colour_fill;
static struct
{
GLuint id;
struct
{
GLint vertex_transform;
GLint texture_coordinate_transform;
GLint colour;
} uniforms;
} program_glyph;
#ifndef USE_OPENGLES2
static GLuint vertex_array_id;
#endif
static GLuint vertex_buffer_id;
static GLuint framebuffer_id;
static VertexBufferSlot *local_vertex_buffer;
static size_t local_vertex_buffer_size;
static size_t current_vertex_buffer_slot;
static RenderMode last_render_mode;
static GLuint last_source_texture;
static GLuint last_destination_texture;
static RenderBackend_Surface *framebuffer_surface;
static RenderBackend_Surface *upscaled_framebuffer_surface;
static RenderBackend_Surface window_surface;
static RenderBackend_Rect window_rect;
#ifdef USE_OPENGLES2
static const GLchar *vertex_shader_plain = " \
#version 100\n \
uniform mat4 vertex_transform; \
attribute vec2 input_vertex_coordinates; \
void main() \
{ \
gl_Position = vec4(input_vertex_coordinates.xy, 0.0, 1.0) * vertex_transform; \
} \
";
static const GLchar *vertex_shader_texture = " \
#version 100\n \
uniform mat4 vertex_transform; \
uniform vec2 texture_coordinate_transform; \
attribute vec2 input_vertex_coordinates; \
attribute vec2 input_texture_coordinates; \
varying vec2 texture_coordinates; \
void main() \
{ \
texture_coordinates = input_texture_coordinates * texture_coordinate_transform; \
gl_Position = vec4(input_vertex_coordinates.xy, 0.0, 1.0) * vertex_transform; \
} \
";
static const GLchar *fragment_shader_texture = " \
#version 100\n \
precision mediump float; \
uniform sampler2D tex; \
varying vec2 texture_coordinates; \
void main() \
{ \
gl_FragColor = texture2D(tex, texture_coordinates); \
} \
";
static const GLchar *fragment_shader_texture_colour_key = " \
#version 100\n \
precision mediump float; \
uniform sampler2D tex; \
varying vec2 texture_coordinates; \
void main() \
{ \
vec4 colour = texture2D(tex, texture_coordinates); \
\
if (colour.xyz == vec3(0.0f, 0.0f, 0.0f)) \
discard; \
\
gl_FragColor = colour; \
} \
";
static const GLchar *fragment_shader_colour_fill = " \
#version 100\n \
precision mediump float; \
uniform vec4 colour; \
void main() \
{ \
gl_FragColor = colour; \
} \
";
static const GLchar *fragment_shader_glyph = " \
#version 100\n \
precision mediump float; \
uniform sampler2D tex; \
uniform vec4 colour; \
varying vec2 texture_coordinates; \
void main() \
{ \
gl_FragColor = colour * vec4(1.0, 1.0, 1.0, texture2D(tex, texture_coordinates).r); \
} \
";
#else
static const GLchar *vertex_shader_plain = " \
#version 150 core\n \
uniform mat4 vertex_transform; \
in vec2 input_vertex_coordinates; \
void main() \
{ \
gl_Position = vec4(input_vertex_coordinates.xy, 0.0, 1.0) * vertex_transform; \
} \
";
static const GLchar *vertex_shader_texture = " \
#version 150 core\n \
uniform mat4 vertex_transform; \
uniform vec2 texture_coordinate_transform; \
in vec2 input_vertex_coordinates; \
in vec2 input_texture_coordinates; \
out vec2 texture_coordinates; \
void main() \
{ \
texture_coordinates = input_texture_coordinates * texture_coordinate_transform; \
gl_Position = vec4(input_vertex_coordinates.xy, 0.0, 1.0) * vertex_transform; \
} \
";
static const GLchar *fragment_shader_texture = " \
#version 150 core\n \
uniform sampler2D tex; \
in vec2 texture_coordinates; \
out vec4 fragment; \
void main() \
{ \
fragment = texture(tex, texture_coordinates); \
} \
";
static const GLchar *fragment_shader_texture_colour_key = " \
#version 150 core\n \
uniform sampler2D tex; \
in vec2 texture_coordinates; \
out vec4 fragment; \
void main() \
{ \
vec4 colour = texture(tex, texture_coordinates); \
\
if (colour.xyz == vec3(0.0f, 0.0f, 0.0f)) \
discard; \
\
fragment = colour; \
} \
";
static const GLchar *fragment_shader_colour_fill = " \
#version 150 core\n \
uniform vec4 colour; \
out vec4 fragment; \
void main() \
{ \
fragment = colour; \
} \
";
static const GLchar *fragment_shader_glyph = " \
#version 150 core\n \
uniform sampler2D tex; \
uniform vec4 colour; \
in vec2 texture_coordinates; \
out vec4 fragment; \
void main() \
{ \
fragment = colour * vec4(1.0, 1.0, 1.0, texture(tex, texture_coordinates).r); \
} \
";
#endif
// A little forward-declaration for some internal functions
static void Blit(RenderBackend_Surface *source_surface, const RenderBackend_Rect *source_rect, RenderBackend_Surface *destination_surface, const RenderBackend_Rect *destination_rect, bool colour_key);
static RenderBackend_Surface* CreateSurface(size_t width, size_t height, bool linear_filter);
// This was used back when CSE2 used GLEW instead of glad
/*
static void GLAPIENTRY MessageCallback(GLenum source, GLenum type, GLuint id, GLenum severity, GLsizei length, const GLchar *message, const void* userParam)
{
(void)source;
(void)type;
(void)id;
(void)length;
(void)userParam;
if (severity != GL_DEBUG_SEVERITY_NOTIFICATION)
Backend_PrintInfo("OpenGL debug: %s", message);
}
*/
static void SetTextureUploadAlignment(size_t pitch)
{
const GLint alignments[8] = {8, 1, 2, 1, 4, 1, 2, 1};
glPixelStorei(GL_UNPACK_ALIGNMENT, alignments[pitch & 7]);
}
////////////////////////
// Shader compilation //
////////////////////////
static GLuint CompileShader(const char *vertex_shader_source, const char *fragment_shader_source)
{
GLint shader_status;
GLuint program_id = glCreateProgram();
// Compile vertex shader
GLuint vertex_shader = glCreateShader(GL_VERTEX_SHADER);
glShaderSource(vertex_shader, 1, &vertex_shader_source, NULL);
glCompileShader(vertex_shader);
glGetShaderiv(vertex_shader, GL_COMPILE_STATUS, &shader_status);
if (shader_status != GL_TRUE)
{
char buffer[0x400];
glGetShaderInfoLog(vertex_shader, sizeof(buffer), NULL, buffer);
Backend_PrintError("Vertex shader error: %s", buffer);
return 0;
}
glAttachShader(program_id, vertex_shader);
// Compile fragment shader
GLuint fragment_shader = glCreateShader(GL_FRAGMENT_SHADER);
glShaderSource(fragment_shader, 1, &fragment_shader_source, NULL);
glCompileShader(fragment_shader);
glGetShaderiv(fragment_shader, GL_COMPILE_STATUS, &shader_status);
if (shader_status != GL_TRUE)
{
char buffer[0x400];
glGetShaderInfoLog(fragment_shader, sizeof(buffer), NULL, buffer);
Backend_PrintError("Fragment shader error: %s", buffer);
return 0;
}
glAttachShader(program_id, fragment_shader);
// Link shaders
glBindAttribLocation(program_id, ATTRIBUTE_INPUT_VERTEX_COORDINATES, "input_vertex_coordinates");
glBindAttribLocation(program_id, ATTRIBUTE_INPUT_TEXTURE_COORDINATES, "input_texture_coordinates");
glLinkProgram(program_id);
glGetProgramiv(program_id, GL_LINK_STATUS, &shader_status);
if (shader_status != GL_TRUE)
{
char buffer[0x400];
glGetProgramInfoLog(program_id, sizeof(buffer), NULL, buffer);
Backend_PrintError("Shader linker error: %s", buffer);
return 0;
}
return program_id;
}
//////////////////////////////
// Vertex buffer management //
//////////////////////////////
static VertexBufferSlot* GetVertexBufferSlot(void)
{
++current_vertex_buffer_slot;
// Check if buffer needs expanding
if (current_vertex_buffer_slot > local_vertex_buffer_size)
{
local_vertex_buffer_size = 1;
while (current_vertex_buffer_slot > local_vertex_buffer_size)
local_vertex_buffer_size <<= 1;
VertexBufferSlot *new_vertex_buffer = (VertexBufferSlot*)realloc(local_vertex_buffer, local_vertex_buffer_size * sizeof(VertexBufferSlot));
if (new_vertex_buffer != NULL)
{
local_vertex_buffer = new_vertex_buffer;
}
else
{
Backend_PrintError("Couldn't expand vertex buffer");
return NULL;
}
}
return &local_vertex_buffer[current_vertex_buffer_slot - 1];
}
static void FlushVertexBuffer(void)
{
if (current_vertex_buffer_slot == 0)
return;
glBufferData(GL_ARRAY_BUFFER, current_vertex_buffer_slot * sizeof(VertexBufferSlot), local_vertex_buffer, GL_STREAM_DRAW);
glDrawArrays(GL_TRIANGLES, 0, 6 * current_vertex_buffer_slot);
current_vertex_buffer_slot = 0;
}
#ifndef USE_OPENGLES2
static const char* GetOpenGLErrorCodeDescription(GLenum error_code)
{
switch (error_code)
{
case GL_NO_ERROR:
return "No error";
case GL_INVALID_ENUM:
return "An unacceptable value was specified for enumerated argument";
case GL_INVALID_VALUE:
return "A numeric argument is out of range";
case GL_INVALID_OPERATION:
return "The specified operation is not allowed in the current state";
case GL_INVALID_FRAMEBUFFER_OPERATION:
return "The framebuffer object is not complete";
case GL_OUT_OF_MEMORY:
return "There is not enough memory left to execute the command";
/*
* For some reason glad does not define these even though they are there in OpenGL 3.2
*/
/*
case GL_STACK_UNDERFLOW:
return "An attempt has been made to perform an operation that would cause an internal stack to underflow";
case GL_STACK_OVERFLOW:
return "An attempt has been made to perform an operation that would cause an internal stack to overflow";
*/
default:
return "Unknown error";
}
}
static void PostGLCallCallback(const char *name, void *function_pointer, int length_arguments, ...)
{
(void)function_pointer;
(void)length_arguments;
GLenum error_code = glad_glGetError(); // Manually use glad_glGetError. Otherwise, glad_debug_glGetError would be called and we'd get infinite recursion into this function
if (error_code != GL_NO_ERROR)
Backend_PrintError("Error %d in %s: %s", error_code, name, GetOpenGLErrorCodeDescription(error_code));
}
#endif
///////////////////////////////////
// Render-backend initialisation //
///////////////////////////////////
RenderBackend_Surface* RenderBackend_Init(const char *window_title, size_t screen_width, size_t screen_height, bool fullscreen)
{
#ifndef USE_OPENGLES2
glad_set_post_callback(PostGLCallCallback);
#endif
size_t actual_screen_width = screen_width;
size_t actual_screen_height = screen_height;
if (WindowBackend_OpenGL_CreateWindow(window_title, &actual_screen_width, &actual_screen_height, fullscreen))
{
Backend_PrintInfo("GL_VENDOR = %s", glGetString(GL_VENDOR));
Backend_PrintInfo("GL_RENDERER = %s", glGetString(GL_RENDERER));
Backend_PrintInfo("GL_VERSION = %s", glGetString(GL_VERSION));
Backend_PrintInfo("GL_SHADING_LANGUAGE_VERSION = %s", glGetString(GL_SHADING_LANGUAGE_VERSION));
// Set up blending (only used for font-rendering)
glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
//glEnable(GL_DEBUG_OUTPUT);
//glDebugMessageCallback(MessageCallback, 0);
glClearColor(0.0f, 0.0f, 0.0f, 1.0f);
glClear(GL_COLOR_BUFFER_BIT);
#ifndef USE_OPENGLES2
// Set up Vertex Array Object
glGenVertexArrays(1, &vertex_array_id);
glBindVertexArray(vertex_array_id);
#endif
// Set up Vertex Buffer Object
glGenBuffers(1, &vertex_buffer_id);
glBindBuffer(GL_ARRAY_BUFFER, vertex_buffer_id);
glVertexAttribPointer(ATTRIBUTE_INPUT_VERTEX_COORDINATES, 2, GL_FLOAT, GL_FALSE, sizeof(Vertex), (GLvoid*)offsetof(Vertex, position));
glVertexAttribPointer(ATTRIBUTE_INPUT_TEXTURE_COORDINATES, 2, GL_FLOAT, GL_FALSE, sizeof(Vertex), (GLvoid*)offsetof(Vertex, texture));
// Set up the vertex attributes
glEnableVertexAttribArray(ATTRIBUTE_INPUT_VERTEX_COORDINATES);
// Set up our shaders
program_texture.id = CompileShader(vertex_shader_texture, fragment_shader_texture);
program_texture_colour_key.id = CompileShader(vertex_shader_texture, fragment_shader_texture_colour_key);
program_colour_fill.id = CompileShader(vertex_shader_plain, fragment_shader_colour_fill);
program_glyph.id = CompileShader(vertex_shader_texture, fragment_shader_glyph);
if (program_texture.id != 0 && program_texture_colour_key.id != 0 && program_colour_fill.id != 0 && program_glyph.id != 0)
{
// Get shader uniforms
program_texture.uniforms.texture_coordinate_transform = glGetUniformLocation(program_texture.id, "texture_coordinate_transform");
program_texture.uniforms.vertex_transform = glGetUniformLocation(program_texture.id, "vertex_transform");
program_texture_colour_key.uniforms.texture_coordinate_transform = glGetUniformLocation(program_texture_colour_key.id, "texture_coordinate_transform");
program_texture_colour_key.uniforms.vertex_transform = glGetUniformLocation(program_texture_colour_key.id, "vertex_transform");
program_colour_fill.uniforms.vertex_transform = glGetUniformLocation(program_colour_fill.id, "vertex_transform");
program_colour_fill.uniforms.colour = glGetUniformLocation(program_colour_fill.id, "colour");
program_glyph.uniforms.texture_coordinate_transform = glGetUniformLocation(program_glyph.id, "texture_coordinate_transform");
program_glyph.uniforms.vertex_transform = glGetUniformLocation(program_glyph.id, "vertex_transform");
program_glyph.uniforms.colour = glGetUniformLocation(program_glyph.id, "colour");
// Set up framebuffer (used for surface-to-surface blitting)
glGenFramebuffers(1, &framebuffer_id);
glBindFramebuffer(GL_FRAMEBUFFER, framebuffer_id);
// Set up framebuffer screen texture (used for screen-to-surface blitting)
framebuffer_surface = RenderBackend_CreateSurface(screen_width, screen_height, true);
// Set up window surface
window_surface.texture_id = 0;
RenderBackend_HandleWindowResize(actual_screen_width, actual_screen_height);
return framebuffer_surface;
}
if (program_glyph.id != 0)
glDeleteProgram(program_glyph.id);
if (program_colour_fill.id != 0)
glDeleteProgram(program_colour_fill.id);
if (program_texture_colour_key.id != 0)
glDeleteProgram(program_texture_colour_key.id);
if (program_texture.id != 0)
glDeleteProgram(program_texture.id);
glDeleteBuffers(1, &vertex_buffer_id);
#ifndef USE_OPENGLES2
glDeleteVertexArrays(1, &vertex_array_id);
#endif
}
return NULL;
}
void RenderBackend_Deinit(void)
{
free(local_vertex_buffer);
if (upscaled_framebuffer_surface != NULL)
RenderBackend_FreeSurface(upscaled_framebuffer_surface);
RenderBackend_FreeSurface(framebuffer_surface);
glDeleteFramebuffers(1, &framebuffer_id);
glDeleteProgram(program_glyph.id);
glDeleteProgram(program_colour_fill.id);
glDeleteProgram(program_texture_colour_key.id);
glDeleteProgram(program_texture.id);
glDeleteBuffers(1, &vertex_buffer_id);
#ifndef USE_OPENGLES2
glDeleteVertexArrays(1, &vertex_array_id);
#endif
WindowBackend_OpenGL_DestroyWindow();
}
void RenderBackend_DrawScreen(void)
{
RenderBackend_Rect framebuffer_rect;
framebuffer_rect.left = 0;
framebuffer_rect.top = 0;
framebuffer_rect.right = framebuffer_surface->width;
framebuffer_rect.bottom = framebuffer_surface->height;
if (upscaled_framebuffer_surface == NULL)
{
Blit(framebuffer_surface, &framebuffer_rect, &window_surface, &window_rect, false);
}
else
{
RenderBackend_Rect upscaled_framebuffer_rect;
upscaled_framebuffer_rect.left = 0;
upscaled_framebuffer_rect.top = 0;
upscaled_framebuffer_rect.right = upscaled_framebuffer_surface->width;
upscaled_framebuffer_rect.bottom = upscaled_framebuffer_surface->height;
Blit(framebuffer_surface, &framebuffer_rect, upscaled_framebuffer_surface, &upscaled_framebuffer_rect, false);
Blit(upscaled_framebuffer_surface, &upscaled_framebuffer_rect, &window_surface, &window_rect, false);
}
// Target actual screen, and not our framebuffer
glBindFramebuffer(GL_FRAMEBUFFER, 0);
// According to https://www.khronos.org/opengl/wiki/Common_Mistakes#Swap_Buffers
// the buffer should always be cleared, even if it seems unnecessary
glClear(GL_COLOR_BUFFER_BIT);
// Flush the vertex buffer, which will render to the screen
FlushVertexBuffer();
WindowBackend_OpenGL_Display();
// Switch back to our framebuffer
glBindFramebuffer(GL_FRAMEBUFFER, framebuffer_id);
}
////////////////////////
// Surface management //
////////////////////////
static RenderBackend_Surface* CreateSurface(size_t width, size_t height, bool linear_filter)
{
RenderBackend_Surface *surface = (RenderBackend_Surface*)malloc(sizeof(RenderBackend_Surface));
if (surface == NULL)
return NULL;
glGenTextures(1, &surface->texture_id);
glBindTexture(GL_TEXTURE_2D, surface->texture_id);
#ifdef USE_OPENGLES2
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, width, height, 0, GL_RGB, GL_UNSIGNED_BYTE, NULL);
#else
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB8, width, height, 0, GL_RGB, GL_UNSIGNED_BYTE, NULL);
#endif
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, linear_filter ? GL_LINEAR : GL_NEAREST);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, linear_filter ? GL_LINEAR : GL_NEAREST);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
#ifndef USE_OPENGLES2
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_R, GL_CLAMP_TO_EDGE);
#endif
glBindTexture(GL_TEXTURE_2D, last_source_texture);
surface->width = width;
surface->height = height;
return surface;
}
RenderBackend_Surface* RenderBackend_CreateSurface(size_t width, size_t height, bool render_target)
{
(void)render_target;
return CreateSurface(width, height, false);
}
void RenderBackend_FreeSurface(RenderBackend_Surface *surface)
{
// Flush the vertex buffer if we're about to destroy its texture
if (surface->texture_id == last_source_texture)
{
FlushVertexBuffer();
last_source_texture = 0;
}
if (surface->texture_id == last_destination_texture)
{
FlushVertexBuffer();
last_destination_texture = 0;
}
glDeleteTextures(1, &surface->texture_id);
free(surface);
}
bool RenderBackend_IsSurfaceLost(RenderBackend_Surface *surface)
{
(void)surface;
return false;
}
void RenderBackend_RestoreSurface(RenderBackend_Surface *surface)
{
(void)surface;
}
void RenderBackend_UploadSurface(RenderBackend_Surface *surface, const unsigned char *pixels, size_t width, size_t height)
{
// Flush the vertex buffer if we're about to modify its texture
if (surface->texture_id == last_source_texture || surface->texture_id == last_destination_texture)
FlushVertexBuffer();
SetTextureUploadAlignment(width * 3);
glBindTexture(GL_TEXTURE_2D, surface->texture_id);
glTexSubImage2D(GL_TEXTURE_2D, 0, 0, 0, width, height, GL_RGB, GL_UNSIGNED_BYTE, pixels);
glBindTexture(GL_TEXTURE_2D, last_source_texture);
}
/////////////
// Drawing //
/////////////
static void Blit(RenderBackend_Surface *source_surface, const RenderBackend_Rect *source_rect, RenderBackend_Surface *destination_surface, const RenderBackend_Rect *destination_rect, bool colour_key)
{
const RenderMode render_mode = (colour_key ? MODE_DRAW_SURFACE_WITH_TRANSPARENCY : MODE_DRAW_SURFACE);
// Flush vertex data if a context-change is needed
if (last_render_mode != render_mode || last_source_texture != source_surface->texture_id || last_destination_texture != destination_surface->texture_id)
{
FlushVertexBuffer();
last_render_mode = render_mode;
last_source_texture = source_surface->texture_id;
last_destination_texture = destination_surface->texture_id;
// Point our framebuffer to the destination texture
glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, destination_surface->texture_id, 0);
glViewport(0, 0, destination_surface->width, destination_surface->height);
GLfloat vertex_transform[4 * 4] = {
2.0f / destination_surface->width, 0.0f, 0.0f, -1.0f,
0.0f, 2.0f / destination_surface->height, 0.0f, -1.0f,
0.0f, 0.0f, 0.0f, 0.0f,
0.0f, 0.0f, 0.0f, 1.0f,
};
// Invert the Y-axis when drawing to the screen, since everything is upside-down in OpenGL for some reason
if (destination_surface->texture_id == 0)
{
vertex_transform[4 + 1] = -vertex_transform[4 + 1];
vertex_transform[4 + 3] = -vertex_transform[4 + 3];
}
// Switch to colour-key shader if we have to
glUseProgram(colour_key ? program_texture_colour_key.id : program_texture.id);
glUniform2f(colour_key ? program_texture_colour_key.uniforms.texture_coordinate_transform : program_texture.uniforms.texture_coordinate_transform, 1.0f / source_surface->width, 1.0f / source_surface->height);
glUniformMatrix4fv(colour_key ? program_texture_colour_key.uniforms.vertex_transform : program_texture.uniforms.vertex_transform, 1, GL_FALSE, vertex_transform);
glDisable(GL_BLEND);
// Enable texture coordinates, since this uses textures
glEnableVertexAttribArray(ATTRIBUTE_INPUT_TEXTURE_COORDINATES);
glBindTexture(GL_TEXTURE_2D, source_surface->texture_id);
}
// Add data to the vertex queue
VertexBufferSlot *vertex_buffer_slot = GetVertexBufferSlot();
if (vertex_buffer_slot != NULL)
{
const GLfloat vertex_left = destination_rect->left;
const GLfloat vertex_top = destination_rect->top;
const GLfloat vertex_right = destination_rect->right;
const GLfloat vertex_bottom = destination_rect->bottom;
vertex_buffer_slot->vertices[0][0].position.x = vertex_left;
vertex_buffer_slot->vertices[0][0].position.y = vertex_top;
vertex_buffer_slot->vertices[0][1].position.x = vertex_right;
vertex_buffer_slot->vertices[0][1].position.y = vertex_top;
vertex_buffer_slot->vertices[0][2].position.x = vertex_right;
vertex_buffer_slot->vertices[0][2].position.y = vertex_bottom;
vertex_buffer_slot->vertices[1][0].position.x = vertex_left;
vertex_buffer_slot->vertices[1][0].position.y = vertex_top;
vertex_buffer_slot->vertices[1][1].position.x = vertex_right;
vertex_buffer_slot->vertices[1][1].position.y = vertex_bottom;
vertex_buffer_slot->vertices[1][2].position.x = vertex_left;
vertex_buffer_slot->vertices[1][2].position.y = vertex_bottom;
const GLfloat texture_left = source_rect->left;
const GLfloat texture_top = source_rect->top;
const GLfloat texture_right = source_rect->right;
const GLfloat texture_bottom = source_rect->bottom;
vertex_buffer_slot->vertices[0][0].texture.x = texture_left;
vertex_buffer_slot->vertices[0][0].texture.y = texture_top;
vertex_buffer_slot->vertices[0][1].texture.x = texture_right;
vertex_buffer_slot->vertices[0][1].texture.y = texture_top;
vertex_buffer_slot->vertices[0][2].texture.x = texture_right;
vertex_buffer_slot->vertices[0][2].texture.y = texture_bottom;
vertex_buffer_slot->vertices[1][0].texture.x = texture_left;
vertex_buffer_slot->vertices[1][0].texture.y = texture_top;
vertex_buffer_slot->vertices[1][1].texture.x = texture_right;
vertex_buffer_slot->vertices[1][1].texture.y = texture_bottom;
vertex_buffer_slot->vertices[1][2].texture.x = texture_left;
vertex_buffer_slot->vertices[1][2].texture.y = texture_bottom;
}
}
void RenderBackend_Blit(RenderBackend_Surface *source_surface, const RenderBackend_Rect *rect, RenderBackend_Surface *destination_surface, long x, long y, bool colour_key)
{
const RenderBackend_Rect destination_rect = {x, y, x + (rect->right - rect->left), y + (rect->bottom - rect->top)};
Blit(source_surface, rect, destination_surface, &destination_rect, colour_key);
}
void RenderBackend_ColourFill(RenderBackend_Surface *surface, const RenderBackend_Rect *rect, unsigned char red, unsigned char green, unsigned char blue)
{
static unsigned char last_red;
static unsigned char last_green;
static unsigned char last_blue;
// Flush vertex data if a context-change is needed
if (last_render_mode != MODE_COLOUR_FILL || last_destination_texture != surface->texture_id || last_red != red || last_green != green || last_blue != blue)
{
FlushVertexBuffer();
last_render_mode = MODE_COLOUR_FILL;
last_source_texture = 0;
last_destination_texture = surface->texture_id;
last_red = red;
last_green = green;
last_blue = blue;
// Point our framebuffer to the destination texture
glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, surface->texture_id, 0);
glViewport(0, 0, surface->width, surface->height);
const GLfloat vertex_transform[4 * 4] = {
2.0f / surface->width, 0.0f, 0.0f, -1.0f,
0.0f, 2.0f / surface->height, 0.0f, -1.0f,
0.0f, 0.0f, 0.0f, 0.0f,
0.0f, 0.0f, 0.0f, 1.0f,
};
glUseProgram(program_colour_fill.id);
glUniformMatrix4fv(program_colour_fill.uniforms.vertex_transform, 1, GL_FALSE, vertex_transform);
glDisable(GL_BLEND);
// Disable texture coordinate array, since this doesn't use textures
glDisableVertexAttribArray(ATTRIBUTE_INPUT_TEXTURE_COORDINATES);
glUniform4f(program_colour_fill.uniforms.colour, red / 255.0f, green / 255.0f, blue / 255.0f, 1.0f);
}
// Add data to the vertex queue
VertexBufferSlot *vertex_buffer_slot = GetVertexBufferSlot();
if (vertex_buffer_slot != NULL)
{
const GLfloat vertex_left = rect->left;
const GLfloat vertex_top = rect->top;
const GLfloat vertex_right = rect->right;
const GLfloat vertex_bottom = rect->bottom;
vertex_buffer_slot->vertices[0][0].position.x = vertex_left;
vertex_buffer_slot->vertices[0][0].position.y = vertex_top;
vertex_buffer_slot->vertices[0][1].position.x = vertex_right;
vertex_buffer_slot->vertices[0][1].position.y = vertex_top;
vertex_buffer_slot->vertices[0][2].position.x = vertex_right;
vertex_buffer_slot->vertices[0][2].position.y = vertex_bottom;
vertex_buffer_slot->vertices[1][0].position.x = vertex_left;
vertex_buffer_slot->vertices[1][0].position.y = vertex_top;
vertex_buffer_slot->vertices[1][1].position.x = vertex_right;
vertex_buffer_slot->vertices[1][1].position.y = vertex_bottom;
vertex_buffer_slot->vertices[1][2].position.x = vertex_left;
vertex_buffer_slot->vertices[1][2].position.y = vertex_bottom;
}
}
//////////////////////
// Glyph management //
//////////////////////
RenderBackend_GlyphAtlas* RenderBackend_CreateGlyphAtlas(size_t width, size_t height)
{
RenderBackend_GlyphAtlas *atlas = (RenderBackend_GlyphAtlas*)malloc(sizeof(RenderBackend_GlyphAtlas));
if (atlas != NULL)
{
atlas->width = width;
atlas->height = height;
glGenTextures(1, &atlas->texture_id);
glBindTexture(GL_TEXTURE_2D, atlas->texture_id);
#ifdef USE_OPENGLES2
glTexImage2D(GL_TEXTURE_2D, 0, GL_LUMINANCE, width, height, 0, GL_LUMINANCE, GL_UNSIGNED_BYTE, NULL);
#else
glTexImage2D(GL_TEXTURE_2D, 0, GL_R8, width, height, 0, GL_RED, GL_UNSIGNED_BYTE, NULL);
#endif
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
#ifndef USE_OPENGLES2
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_R, GL_CLAMP_TO_EDGE);
#endif
glBindTexture(GL_TEXTURE_2D, last_source_texture);
}
return atlas;
}
void RenderBackend_DestroyGlyphAtlas(RenderBackend_GlyphAtlas *atlas)
{
glDeleteTextures(1, &atlas->texture_id);
free(atlas);
}
void RenderBackend_UploadGlyph(RenderBackend_GlyphAtlas *atlas, size_t x, size_t y, const unsigned char *pixels, size_t width, size_t height, size_t pitch)
{
#ifdef USE_OPENGLES2
unsigned char *buffer = (unsigned char*)malloc(width * height);
if (buffer == NULL)
return;
for (size_t y = 0; y < height; ++y)
memcpy (&buffer[y * width], &pixels[y * pitch], width);
#else
const unsigned char *buffer = pixels;
glPixelStorei(GL_UNPACK_ROW_LENGTH, pitch);
#endif
SetTextureUploadAlignment(width);
glBindTexture(GL_TEXTURE_2D, atlas->texture_id);
#ifdef USE_OPENGLES2
glTexSubImage2D(GL_TEXTURE_2D, 0, x, y, width, height, GL_LUMINANCE, GL_UNSIGNED_BYTE, buffer);
#else
glTexSubImage2D(GL_TEXTURE_2D, 0, x, y, width, height, GL_RED, GL_UNSIGNED_BYTE, buffer);
#endif
glBindTexture(GL_TEXTURE_2D, last_source_texture);
#ifdef USE_OPENGLES2
free(buffer);
#else
glPixelStorei(GL_UNPACK_ROW_LENGTH, 0);
#endif
}
void RenderBackend_PrepareToDrawGlyphs(RenderBackend_GlyphAtlas *atlas, RenderBackend_Surface *destination_surface, unsigned char red, unsigned char green, unsigned char blue)
{
static unsigned char last_red;
static unsigned char last_green;
static unsigned char last_blue;
// Flush vertex data if a context-change is needed
if (last_render_mode != MODE_DRAW_GLYPH || last_source_texture != atlas->texture_id || last_destination_texture != destination_surface->texture_id || last_red != red || last_green != green || last_blue != blue)
{
FlushVertexBuffer();
last_render_mode = MODE_DRAW_GLYPH;
last_source_texture = atlas->texture_id;
last_destination_texture = destination_surface->texture_id;
last_red = red;
last_green = green;
last_blue = blue;
const GLfloat vertex_transform[4 * 4] = {
2.0f / destination_surface->width, 0.0f, 0.0f, -1.0f,
0.0f, 2.0f / destination_surface->height, 0.0f, -1.0f,
0.0f, 0.0f, 1.0f, 0.0f,
0.0f, 0.0f, 0.0f, 1.0f,
};
glUseProgram(program_glyph.id);
glUniform2f(program_glyph.uniforms.texture_coordinate_transform, 1.0f / atlas->width, 1.0f / atlas->height);
glUniform4f(program_glyph.uniforms.colour, red / 255.0f, green / 255.0f, blue / 255.0f, 1.0f);
glUniformMatrix4fv(program_glyph.uniforms.vertex_transform, 1, GL_FALSE, vertex_transform);
// Point our framebuffer to the destination texture
glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, destination_surface->texture_id, 0);
glViewport(0, 0, destination_surface->width, destination_surface->height);
glEnable(GL_BLEND);
// Enable texture coordinates, since this uses textures
glEnableVertexAttribArray(ATTRIBUTE_INPUT_TEXTURE_COORDINATES);
glBindTexture(GL_TEXTURE_2D, atlas->texture_id);
}
}
void RenderBackend_DrawGlyph(long x, long y, size_t glyph_x, size_t glyph_y, size_t glyph_width, size_t glyph_height)
{
// Add data to the vertex queue
VertexBufferSlot *vertex_buffer_slot = GetVertexBufferSlot();
if (vertex_buffer_slot != NULL)
{
const GLfloat vertex_left = x;
const GLfloat vertex_top = y;
const GLfloat vertex_right = x + glyph_width;
const GLfloat vertex_bottom = y + glyph_height;
vertex_buffer_slot->vertices[0][0].position.x = vertex_left;
vertex_buffer_slot->vertices[0][0].position.y = vertex_top;
vertex_buffer_slot->vertices[0][1].position.x = vertex_right;
vertex_buffer_slot->vertices[0][1].position.y = vertex_top;
vertex_buffer_slot->vertices[0][2].position.x = vertex_right;
vertex_buffer_slot->vertices[0][2].position.y = vertex_bottom;
vertex_buffer_slot->vertices[1][0].position.x = vertex_left;
vertex_buffer_slot->vertices[1][0].position.y = vertex_top;
vertex_buffer_slot->vertices[1][1].position.x = vertex_right;
vertex_buffer_slot->vertices[1][1].position.y = vertex_bottom;
vertex_buffer_slot->vertices[1][2].position.x = vertex_left;
vertex_buffer_slot->vertices[1][2].position.y = vertex_bottom;
const GLfloat texture_left = glyph_x;
const GLfloat texture_top = glyph_y;
const GLfloat texture_right = glyph_x + glyph_width;
const GLfloat texture_bottom = glyph_y + glyph_height;
vertex_buffer_slot->vertices[0][0].texture.x = texture_left;
vertex_buffer_slot->vertices[0][0].texture.y = texture_top;
vertex_buffer_slot->vertices[0][1].texture.x = texture_right;
vertex_buffer_slot->vertices[0][1].texture.y = texture_top;
vertex_buffer_slot->vertices[0][2].texture.x = texture_right;
vertex_buffer_slot->vertices[0][2].texture.y = texture_bottom;
vertex_buffer_slot->vertices[1][0].texture.x = texture_left;
vertex_buffer_slot->vertices[1][0].texture.y = texture_top;
vertex_buffer_slot->vertices[1][1].texture.x = texture_right;
vertex_buffer_slot->vertices[1][1].texture.y = texture_bottom;
vertex_buffer_slot->vertices[1][2].texture.x = texture_left;
vertex_buffer_slot->vertices[1][2].texture.y = texture_bottom;
}
}
///////////
// Misc. //
///////////
void RenderBackend_HandleRenderTargetLoss(void)
{
// No problem for us
}
void RenderBackend_HandleWindowResize(size_t width, size_t height)
{
size_t upscale_factor = MAX(1, MIN((width + framebuffer_surface->width / 2) / framebuffer_surface->width, (height + framebuffer_surface->height / 2) / framebuffer_surface->height));
size_t upscaled_framebuffer_width = framebuffer_surface->width * upscale_factor;
size_t upscaled_framebuffer_height = framebuffer_surface->height * upscale_factor;
if (upscaled_framebuffer_surface != NULL)
{
RenderBackend_FreeSurface(upscaled_framebuffer_surface);
upscaled_framebuffer_surface = NULL;
}
// Create rect that forces 4:3 no matter what size the window is
if (width * upscaled_framebuffer_height >= upscaled_framebuffer_width * height) // Fancy way to do `if (width / height >= upscaled_framebuffer->width / upscaled_framebuffer->height)` without floats
{
window_rect.right = (height * upscaled_framebuffer_width) / upscaled_framebuffer_height;
window_rect.bottom = height;
}
else
{
window_rect.right = width;
window_rect.bottom = (width * upscaled_framebuffer_height) / upscaled_framebuffer_width;
}
window_rect.left = (width - window_rect.right) / 2;
window_rect.top = (height - window_rect.bottom) / 2;
window_rect.right += window_rect.left;
window_rect.bottom += window_rect.top;
window_surface.width = width;
window_surface.height = height;
if ((window_rect.right - window_rect.left) % framebuffer_surface->width != 0 || (window_rect.bottom - window_rect.top) % framebuffer_surface->height != 0)
{
upscaled_framebuffer_surface = CreateSurface(upscaled_framebuffer_width, upscaled_framebuffer_height, true);
if (upscaled_framebuffer_surface == NULL)
Backend_PrintError("Couldn't regenerate upscaled framebuffer");
}
}