ref: 4c024b540f755ca4679f826026e4843328cccb9e
parent: 2c9531062bfa7e5b994718a7449d63180128d389
author: Clownacy <Clownacy@users.noreply.github.com>
date: Wed Jul 31 18:33:22 EDT 2019
Migrated OpenGL backend to OpenGL 3.2 Goddammit 3.2 is so complex. The reason I want 3.2 is because I'm not convinced Legacy OpenGL will be well-supported in the future. 3.2 is about as far back as I can go without breaking forward-compatibility (it was the first version to introduce the Core Profile).
--- a/src/Backends/Rendering/OpenGL2.cpp
+++ b/src/Backends/Rendering/OpenGL2.cpp
@@ -37,14 +37,19 @@
static GLint program_glyph_uniform_colour;
static GLuint framebuffer_id;
-static GLfloat vertex_buffer[4][2];
-static GLfloat texture_coordinate_buffer[4][2];
+static GLuint vertex_buffer_id;
+static struct
+{+ GLfloat vertexes[4][2];
+ GLfloat texture_coordinates[4][2];
+} vertex_buffer;
+
static Backend_Surface framebuffer_surface;
static const GLchar *vertex_shader_plain = " \
-#version 120\n \
-attribute vec2 input_vertex_coordinates; \
+#version 150 core\n \
+in vec2 input_vertex_coordinates; \
void main() \
{ \gl_Position = vec4(input_vertex_coordinates.x, input_vertex_coordinates.y, 0.0, 1.0); \
@@ -52,10 +57,10 @@
";
static const GLchar *vertex_shader_texture = " \
-#version 120\n \
-attribute vec2 input_vertex_coordinates; \
-attribute vec2 input_texture_coordinates; \
-varying vec2 texture_coordinates; \
+#version 150 core\n \
+in vec2 input_vertex_coordinates; \
+in vec2 input_texture_coordinates; \
+out vec2 texture_coordinates; \
void main() \
{ \texture_coordinates = input_texture_coordinates; \
@@ -64,19 +69,21 @@
";
static const GLchar *fragment_shader_texture = " \
-#version 120\n \
+#version 150 core\n \
uniform sampler2D tex; \
-varying vec2 texture_coordinates; \
+in vec2 texture_coordinates; \
+out vec4 fragment; \
void main() \
{ \- gl_FragColor = texture2D(tex, texture_coordinates); \
+ fragment = texture2D(tex, texture_coordinates); \
} \
";
static const GLchar *fragment_shader_texture_colour_key = " \
-#version 120\n \
+#version 150 core\n \
uniform sampler2D tex; \
-varying vec2 texture_coordinates; \
+in vec2 texture_coordinates; \
+out vec4 fragment; \
void main() \
{ \vec4 colour = texture2D(tex, texture_coordinates); \
@@ -84,30 +91,40 @@
if (colour.xyz == vec3(0.0f, 0.0f, 0.0f)) \
discard; \
\
- gl_FragColor = colour; \
+ fragment = colour; \
} \
";
static const GLchar *fragment_shader_colour_fill = " \
-#version 120\n \
+#version 150 core\n \
uniform vec4 colour; \
+out vec4 fragment; \
void main() \
{ \- gl_FragColor = colour; \
+ fragment = colour; \
} \
";
static const GLchar *fragment_shader_glyph = " \
-#version 120\n \
+#version 150 core\n \
uniform sampler2D tex; \
uniform vec4 colour; \
-varying vec2 texture_coordinates; \
+in vec2 texture_coordinates; \
+out vec4 fragment; \
void main() \
{ \- gl_FragColor = colour * texture2D(tex, texture_coordinates); \
+ fragment = colour * vec4(1.0, 1.0, 1.0, texture2D(tex, texture_coordinates).r); \
} \
";
+static void GLAPIENTRY MessageCallback(GLenum source, GLenum type, GLuint id, GLenum severity, GLsizei length, const GLchar *message, const void* userParam)
+{+ if (type == GL_DEBUG_TYPE_ERROR)
+ printf("GL CALLBACK: %s type = 0x%x, severity = 0x%x, message = %s\n",+ ( type == GL_DEBUG_TYPE_ERROR ? "** GL ERROR **" : "" ),
+ type, severity, message);
+}
+
static GLuint CompileShader(const char *vertex_shader_source, const char *fragment_shader_source)
{GLint shader_status;
@@ -148,9 +165,9 @@
SDL_Window* Backend_CreateWindow(const char *title, int width, int height)
{- SDL_GL_SetAttribute(SDL_GL_CONTEXT_PROFILE_MASK, SDL_GL_CONTEXT_PROFILE_COMPATIBILITY);
- SDL_GL_SetAttribute(SDL_GL_CONTEXT_MAJOR_VERSION, 2);
- SDL_GL_SetAttribute(SDL_GL_CONTEXT_MINOR_VERSION, 1);
+ SDL_GL_SetAttribute(SDL_GL_CONTEXT_PROFILE_MASK, SDL_GL_CONTEXT_PROFILE_CORE);
+ SDL_GL_SetAttribute(SDL_GL_CONTEXT_MAJOR_VERSION, 3);
+ SDL_GL_SetAttribute(SDL_GL_CONTEXT_MINOR_VERSION, 2);
return SDL_CreateWindow(title, SDL_WINDOWPOS_CENTERED, SDL_WINDOWPOS_CENTERED, width, height, SDL_WINDOW_OPENGL);
}
@@ -167,13 +184,13 @@
if (glewInit() != GLEW_OK)
return FALSE;
- // Check if the platform supports OpenGL 2.1
- if (!GLEW_VERSION_2_1)
+ // Check if the platform supports OpenGL 3.2
+ if (!GLEW_VERSION_3_2)
return FALSE;
- // Check for framebuffer object extension (is part of the core spec in OpenGL 3.0, but not 2.1)
- if (!GLEW_EXT_framebuffer_object)
- return FALSE;
+ // During init, enable debug output
+ glEnable(GL_DEBUG_OUTPUT);
+ glDebugMessageCallback(MessageCallback, 0);
glEnable(GL_BLEND);
glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
@@ -181,6 +198,23 @@
glClearColor(0.0f, 0.0f, 0.0f, 1.0f);
glClear(GL_COLOR_BUFFER_BIT);
+ // Set up VAO
+ GLuint vertex_array_id;
+ glGenVertexArrays(1, &vertex_array_id);
+ glBindVertexArray(vertex_array_id);
+
+ // Set up VBO
+ glGenBuffers(1, &vertex_buffer_id);
+ glBindBuffer(GL_ARRAY_BUFFER, vertex_buffer_id);
+ glBufferData(GL_ARRAY_BUFFER, sizeof(vertex_buffer), NULL, GL_DYNAMIC_DRAW);
+
+ // Set up IBO
+ const GLuint indices[4] = {0, 1, 2, 3};+ GLuint indices_buffer_id;
+ glGenBuffers(1, &indices_buffer_id);
+ glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, indices_buffer_id);
+ glBufferData(GL_ELEMENT_ARRAY_BUFFER, sizeof(indices), indices, GL_STATIC_DRAW);
+
// Set up our shaders
program_texture = CompileShader(vertex_shader_texture, fragment_shader_texture);
program_texture_colour_key = CompileShader(vertex_shader_texture, fragment_shader_texture_colour_key);
@@ -195,12 +229,12 @@
program_glyph_uniform_colour = glGetUniformLocation(program_glyph, "colour");
glEnableVertexAttribArray(1);
- glVertexAttribPointer(1, 2, GL_FLOAT, GL_FALSE, 0, vertex_buffer);
- glVertexAttribPointer(2, 2, GL_FLOAT, GL_FALSE, 0, texture_coordinate_buffer);
+ glVertexAttribPointer(1, 2, GL_FLOAT, GL_FALSE, 0, 0);
+ glVertexAttribPointer(2, 2, GL_FLOAT, GL_FALSE, 0, (GLvoid*)(sizeof(GLfloat) * 4 * 2));
// Set up framebuffer (used for surface-to-surface blitting)
- glGenFramebuffersEXT(1, &framebuffer_id);
- glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, framebuffer_id);
+ glGenFramebuffers(1, &framebuffer_id);
+ glBindFramebuffer(GL_FRAMEBUFFER, framebuffer_id);
// Set up framebuffer screen texture (used for screen-to-surface blitting)
glGenTextures(1, &framebuffer_surface.texture_id);
@@ -218,7 +252,7 @@
void Backend_Deinit(void)
{glDeleteTextures(1, &framebuffer_surface.texture_id);
- glDeleteFramebuffersEXT(1, &framebuffer_id);
+ glDeleteFramebuffers(1, &framebuffer_id);
glDeleteProgram(program_glyph);
glDeleteProgram(program_colour_fill);
glDeleteProgram(program_texture_colour_key);
@@ -234,7 +268,7 @@
glEnableVertexAttribArray(2);
// Target actual screen, and not our framebuffer
- glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, 0);
+ glBindFramebuffer(GL_FRAMEBUFFER, 0);
glViewport(0, 0, framebuffer_surface.width, framebuffer_surface.height);
@@ -241,25 +275,26 @@
// Draw framebuffer to screen
glBindTexture(GL_TEXTURE_2D, framebuffer_surface.texture_id);
- texture_coordinate_buffer[0][0] = 0.0f;
- texture_coordinate_buffer[0][1] = 1.0f;
- texture_coordinate_buffer[1][0] = 1.0f;
- texture_coordinate_buffer[1][1] = 1.0f;
- texture_coordinate_buffer[2][0] = 1.0f;
- texture_coordinate_buffer[2][1] = 0.0f;
- texture_coordinate_buffer[3][0] = 0.0f;
- texture_coordinate_buffer[3][1] = 0.0f;
+ vertex_buffer.texture_coordinates[0][0] = 0.0f;
+ vertex_buffer.texture_coordinates[0][1] = 1.0f;
+ vertex_buffer.texture_coordinates[1][0] = 1.0f;
+ vertex_buffer.texture_coordinates[1][1] = 1.0f;
+ vertex_buffer.texture_coordinates[2][0] = 1.0f;
+ vertex_buffer.texture_coordinates[2][1] = 0.0f;
+ vertex_buffer.texture_coordinates[3][0] = 0.0f;
+ vertex_buffer.texture_coordinates[3][1] = 0.0f;
- vertex_buffer[0][0] = -1.0f;
- vertex_buffer[0][1] = -1.0f;
- vertex_buffer[1][0] = 1.0f;
- vertex_buffer[1][1] = -1.0f;
- vertex_buffer[2][0] = 1.0f;
- vertex_buffer[2][1] = 1.0f;
- vertex_buffer[3][0] = -1.0f;
- vertex_buffer[3][1] = 1.0f;
+ vertex_buffer.vertexes[0][0] = -1.0f;
+ vertex_buffer.vertexes[0][1] = -1.0f;
+ vertex_buffer.vertexes[1][0] = 1.0f;
+ vertex_buffer.vertexes[1][1] = -1.0f;
+ vertex_buffer.vertexes[2][0] = 1.0f;
+ vertex_buffer.vertexes[2][1] = 1.0f;
+ vertex_buffer.vertexes[3][0] = -1.0f;
+ vertex_buffer.vertexes[3][1] = 1.0f;
- glDrawArrays(GL_TRIANGLE_FAN, 0, 4);
+ glBufferSubData(GL_ARRAY_BUFFER, 0, sizeof(vertex_buffer), &vertex_buffer);
+ glDrawElements(GL_TRIANGLE_FAN, 4, GL_UNSIGNED_INT, NULL);
SDL_GL_SwapWindow(window);
@@ -268,7 +303,7 @@
glClear(GL_COLOR_BUFFER_BIT);
// Switch back to our framebuffer
- glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, framebuffer_id);
+ glBindFramebuffer(GL_FRAMEBUFFER, framebuffer_id);
}
Backend_Surface* Backend_CreateSurface(unsigned int width, unsigned int height)
@@ -342,25 +377,26 @@
const GLfloat vertex_top = (y * (2.0f / destination_surface->height)) - 1.0f;
const GLfloat vertex_bottom = ((y + (rect->bottom - rect->top)) * (2.0f / destination_surface->height)) - 1.0f;
- texture_coordinate_buffer[0][0] = texture_left;
- texture_coordinate_buffer[0][1] = texture_top;
- texture_coordinate_buffer[1][0] = texture_right;
- texture_coordinate_buffer[1][1] = texture_top;
- texture_coordinate_buffer[2][0] = texture_right;
- texture_coordinate_buffer[2][1] = texture_bottom;
- texture_coordinate_buffer[3][0] = texture_left;
- texture_coordinate_buffer[3][1] = texture_bottom;
+ vertex_buffer.texture_coordinates[0][0] = texture_left;
+ vertex_buffer.texture_coordinates[0][1] = texture_top;
+ vertex_buffer.texture_coordinates[1][0] = texture_right;
+ vertex_buffer.texture_coordinates[1][1] = texture_top;
+ vertex_buffer.texture_coordinates[2][0] = texture_right;
+ vertex_buffer.texture_coordinates[2][1] = texture_bottom;
+ vertex_buffer.texture_coordinates[3][0] = texture_left;
+ vertex_buffer.texture_coordinates[3][1] = texture_bottom;
- vertex_buffer[0][0] = vertex_left;
- vertex_buffer[0][1] = vertex_top;
- vertex_buffer[1][0] = vertex_right;
- vertex_buffer[1][1] = vertex_top;
- vertex_buffer[2][0] = vertex_right;
- vertex_buffer[2][1] = vertex_bottom;
- vertex_buffer[3][0] = vertex_left;
- vertex_buffer[3][1] = vertex_bottom;
+ vertex_buffer.vertexes[0][0] = vertex_left;
+ vertex_buffer.vertexes[0][1] = vertex_top;
+ vertex_buffer.vertexes[1][0] = vertex_right;
+ vertex_buffer.vertexes[1][1] = vertex_top;
+ vertex_buffer.vertexes[2][0] = vertex_right;
+ vertex_buffer.vertexes[2][1] = vertex_bottom;
+ vertex_buffer.vertexes[3][0] = vertex_left;
+ vertex_buffer.vertexes[3][1] = vertex_bottom;
- glDrawArrays(GL_TRIANGLE_FAN, 0, 4);
+ glBufferSubData(GL_ARRAY_BUFFER, 0, sizeof(vertex_buffer), &vertex_buffer);
+ glDrawElements(GL_TRIANGLE_FAN, 4, GL_UNSIGNED_INT, NULL);
}
void Backend_Blit(Backend_Surface *source_surface, const RECT *rect, Backend_Surface *destination_surface, long x, long y, BOOL colour_key)
@@ -369,7 +405,7 @@
return;
// Point our framebuffer to the destination texture
- glFramebufferTexture2DEXT(GL_FRAMEBUFFER_EXT, GL_COLOR_ATTACHMENT0_EXT, GL_TEXTURE_2D, destination_surface->texture_id, 0);
+ glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, destination_surface->texture_id, 0);
glViewport(0, 0, destination_surface->width, destination_surface->height);
BlitCommon(source_surface, rect, destination_surface, x, y, colour_key);
@@ -381,7 +417,7 @@
return;
// Point our framebuffer to the screen texture
- glFramebufferTexture2DEXT(GL_FRAMEBUFFER_EXT, GL_COLOR_ATTACHMENT0_EXT, GL_TEXTURE_2D, framebuffer_surface.texture_id, 0);
+ glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, framebuffer_surface.texture_id, 0);
glViewport(0, 0, framebuffer_surface.width, framebuffer_surface.height);
BlitCommon(source_surface, rect, &framebuffer_surface, x, y, colour_key);
@@ -404,16 +440,17 @@
const GLfloat vertex_top = (rect->top * (2.0f / surface->height)) - 1.0f;
const GLfloat vertex_bottom = (rect->bottom * (2.0f / surface->height)) - 1.0f;
- vertex_buffer[0][0] = vertex_left;
- vertex_buffer[0][1] = vertex_top;
- vertex_buffer[1][0] = vertex_right;
- vertex_buffer[1][1] = vertex_top;
- vertex_buffer[2][0] = vertex_right;
- vertex_buffer[2][1] = vertex_bottom;
- vertex_buffer[3][0] = vertex_left;
- vertex_buffer[3][1] = vertex_bottom;
+ vertex_buffer.vertexes[0][0] = vertex_left;
+ vertex_buffer.vertexes[0][1] = vertex_top;
+ vertex_buffer.vertexes[1][0] = vertex_right;
+ vertex_buffer.vertexes[1][1] = vertex_top;
+ vertex_buffer.vertexes[2][0] = vertex_right;
+ vertex_buffer.vertexes[2][1] = vertex_bottom;
+ vertex_buffer.vertexes[3][0] = vertex_left;
+ vertex_buffer.vertexes[3][1] = vertex_bottom;
- glDrawArrays(GL_TRIANGLE_FAN, 0, 4);
+ glBufferSubData(GL_ARRAY_BUFFER, 0, sizeof(vertex_buffer), &vertex_buffer);
+ glDrawElements(GL_TRIANGLE_FAN, 4, GL_UNSIGNED_INT, NULL);
}
void Backend_ColourFill(Backend_Surface *surface, const RECT *rect, unsigned char red, unsigned char green, unsigned char blue)
@@ -422,7 +459,7 @@
return;
// Point our framebuffer to the destination texture
- glFramebufferTexture2DEXT(GL_FRAMEBUFFER_EXT, GL_COLOR_ATTACHMENT0_EXT, GL_TEXTURE_2D, surface->texture_id, 0);
+ glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, surface->texture_id, 0);
glViewport(0, 0, surface->width, surface->height);
ColourFillCommon(surface, rect, red, green, blue);
@@ -431,7 +468,7 @@
void Backend_ColourFillToScreen(const RECT *rect, unsigned char red, unsigned char green, unsigned char blue)
{// Point our framebuffer to the screen texture
- glFramebufferTexture2DEXT(GL_FRAMEBUFFER_EXT, GL_COLOR_ATTACHMENT0_EXT, GL_TEXTURE_2D, framebuffer_surface.texture_id, 0);
+ glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, framebuffer_surface.texture_id, 0);
glViewport(0, 0, framebuffer_surface.width, framebuffer_surface.height);
ColourFillCommon(&framebuffer_surface, rect, red, green, blue);
@@ -443,7 +480,7 @@
return;
// Point our framebuffer to the destination texture
- glFramebufferTexture2DEXT(GL_FRAMEBUFFER_EXT, GL_COLOR_ATTACHMENT0_EXT, GL_TEXTURE_2D, surface->texture_id, 0);
+ glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, surface->texture_id, 0);
glViewport(0, 0, surface->width, surface->height);
BlitCommon(&framebuffer_surface, rect, surface, rect->left, rect->top, FALSE);
@@ -461,7 +498,7 @@
if (glyph == NULL)
return NULL;
- const int destination_pitch = ((width * 2) + 3) & ~3; // Round up to the nearest 4 (OpenGL needs this)
+ const int destination_pitch = (width + 3) & ~3; // Round up to the nearest 4 (OpenGL needs this)
unsigned char *buffer = (unsigned char*)malloc(destination_pitch * height);
@@ -483,7 +520,6 @@
for (unsigned int x = 0; x < width; ++x)
{- *destination_pointer++ = 0xFF;
*destination_pointer++ = (unsigned char)(pow((double)*source_pointer++ / (total_greys - 1), 1.0 / 1.8) * 255.0);
}
}
@@ -498,7 +534,6 @@
for (unsigned int x = 0; x < width; ++x)
{- *destination_pointer++ = 0xFF;
*destination_pointer++ = *source_pointer++ ? 0xFF : 0;
}
}
@@ -508,7 +543,7 @@
glGenTextures(1, &glyph->texture_id);
glBindTexture(GL_TEXTURE_2D, glyph->texture_id);
- glTexImage2D(GL_TEXTURE_2D, 0, GL_LUMINANCE8_ALPHA8, width, height, 0, GL_LUMINANCE_ALPHA, GL_UNSIGNED_BYTE, buffer);
+ glTexImage2D(GL_TEXTURE_2D, 0, GL_R8, width, height, 0, GL_RED, GL_UNSIGNED_BYTE, buffer);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
@@ -545,25 +580,26 @@
glUniform4f(program_glyph_uniform_colour, colours[0] / 255.0f, colours[1] / 255.0f, colours[2] / 255.0f, 1.0f);
- texture_coordinate_buffer[0][0] = 0.0f;
- texture_coordinate_buffer[0][1] = 0.0f;
- texture_coordinate_buffer[1][0] = 1.0f;
- texture_coordinate_buffer[1][1] = 0.0f;
- texture_coordinate_buffer[2][0] = 1.0f;
- texture_coordinate_buffer[2][1] = 1.0f;
- texture_coordinate_buffer[3][0] = 0.0f;
- texture_coordinate_buffer[3][1] = 1.0f;
+ vertex_buffer.texture_coordinates[0][0] = 0.0f;
+ vertex_buffer.texture_coordinates[0][1] = 0.0f;
+ vertex_buffer.texture_coordinates[1][0] = 1.0f;
+ vertex_buffer.texture_coordinates[1][1] = 0.0f;
+ vertex_buffer.texture_coordinates[2][0] = 1.0f;
+ vertex_buffer.texture_coordinates[2][1] = 1.0f;
+ vertex_buffer.texture_coordinates[3][0] = 0.0f;
+ vertex_buffer.texture_coordinates[3][1] = 1.0f;
- vertex_buffer[0][0] = vertex_left;
- vertex_buffer[0][1] = vertex_top;
- vertex_buffer[1][0] = vertex_right;
- vertex_buffer[1][1] = vertex_top;
- vertex_buffer[2][0] = vertex_right;
- vertex_buffer[2][1] = vertex_bottom;
- vertex_buffer[3][0] = vertex_left;
- vertex_buffer[3][1] = vertex_bottom;
+ vertex_buffer.vertexes[0][0] = vertex_left;
+ vertex_buffer.vertexes[0][1] = vertex_top;
+ vertex_buffer.vertexes[1][0] = vertex_right;
+ vertex_buffer.vertexes[1][1] = vertex_top;
+ vertex_buffer.vertexes[2][0] = vertex_right;
+ vertex_buffer.vertexes[2][1] = vertex_bottom;
+ vertex_buffer.vertexes[3][0] = vertex_left;
+ vertex_buffer.vertexes[3][1] = vertex_bottom;
- glDrawArrays(GL_TRIANGLE_FAN, 0, 4);
+ glBufferSubData(GL_ARRAY_BUFFER, 0, sizeof(vertex_buffer), &vertex_buffer);
+ glDrawElements(GL_TRIANGLE_FAN, 4, GL_UNSIGNED_INT, NULL);
}
void Backend_DrawGlyph(Backend_Surface *surface, Backend_Glyph *glyph, long x, long y, const unsigned char *colours)
@@ -572,7 +608,7 @@
return;
// Point our framebuffer to the destination texture
- glFramebufferTexture2DEXT(GL_FRAMEBUFFER_EXT, GL_COLOR_ATTACHMENT0_EXT, GL_TEXTURE_2D, surface->texture_id, 0);
+ glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, surface->texture_id, 0);
glViewport(0, 0, surface->width, surface->height);
DrawGlyphCommon(surface, glyph, x, y, colours);
@@ -584,7 +620,7 @@
return;
// Point our framebuffer to the screen texture
- glFramebufferTexture2DEXT(GL_FRAMEBUFFER_EXT, GL_COLOR_ATTACHMENT0_EXT, GL_TEXTURE_2D, framebuffer_surface.texture_id, 0);
+ glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, framebuffer_surface.texture_id, 0);
glViewport(0, 0, framebuffer_surface.width, framebuffer_surface.height);
DrawGlyphCommon(&framebuffer_surface, glyph, x, y, colours);