Initial commit
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snesrev
220
src/opengl.c
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220
src/opengl.c
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#include "third_party/gl_core/gl_core_3_1.h"
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#include <SDL.h>
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#include <stdio.h>
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#include <stdbool.h>
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#include "types.h"
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#include "util.h"
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#include "glsl_shader.h"
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#include "config.h"
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#define CODE(...) #__VA_ARGS__
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static SDL_Window *g_window;
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static uint8 *g_screen_buffer;
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static size_t g_screen_buffer_size;
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static int g_draw_width, g_draw_height;
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static unsigned int g_program, g_VAO;
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static GlTextureWithSize g_texture;
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static GlslShader *g_glsl_shader;
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static void GL_APIENTRY MessageCallback(GLenum source,
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GLenum type,
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GLuint id,
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GLenum severity,
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GLsizei length,
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const GLchar *message,
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const void *userParam) {
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if (type == GL_DEBUG_TYPE_OTHER)
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return;
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fprintf(stderr, "GL CALLBACK: %s type = 0x%x, severity = 0x%x, message = %s\n",
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(type == GL_DEBUG_TYPE_ERROR ? "** GL ERROR **" : ""),
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type, severity, message);
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if (type == GL_DEBUG_TYPE_ERROR)
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Die("OpenGL error!\n");
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}
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static bool OpenGLRenderer_Init(SDL_Window *window) {
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g_window = window;
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SDL_GLContext context = SDL_GL_CreateContext(window);
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(void)context;
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SDL_GL_SetSwapInterval(1);
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ogl_LoadFunctions();
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if (!ogl_IsVersionGEQ(3, 3))
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Die("You need OpenGL 3.3");
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if (kDebugFlag) {
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glEnable(GL_DEBUG_OUTPUT);
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glEnable(GL_DEBUG_OUTPUT_SYNCHRONOUS);
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glDebugMessageCallback(MessageCallback, 0);
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}
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glGenTextures(1, &g_texture.gl_texture);
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static const float kVertices[] = {
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// positions // texture coords
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-1.0f, 1.0f, 0.0f, 0.0f, 0.0f, // top left
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-1.0f, -1.0f, 0.0f, 0.0f, 1.0f, // bottom left
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1.0f, 1.0f, 0.0f, 1.0f, 0.0f, // top right
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1.0f, -1.0f, 0.0f, 1.0f, 1.0f, // bottom right
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};
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// create a vertex buffer object
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unsigned int vbo;
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glGenBuffers(1, &vbo);
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// vertex array object
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glGenVertexArrays(1, &g_VAO);
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// 1. bind Vertex Array Object
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glBindVertexArray(g_VAO);
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// 2. copy our vertices array in a buffer for OpenGL to use
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glBindBuffer(GL_ARRAY_BUFFER, vbo);
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glBufferData(GL_ARRAY_BUFFER, sizeof(kVertices), kVertices, GL_STATIC_DRAW);
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// position attribute
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glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 5 * sizeof(float), (void *)0);
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glEnableVertexAttribArray(0);
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// texture coord attribute
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glVertexAttribPointer(1, 2, GL_FLOAT, GL_FALSE, 5 * sizeof(float), (void *)(3 * sizeof(float)));
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glEnableVertexAttribArray(1);
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// vertex shader
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const GLchar *vs_code = "#version 330 core\n" CODE(
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layout(location = 0) in vec3 aPos;
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layout(location = 1) in vec2 aTexCoord;
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out vec2 TexCoord;
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void main(void) {
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gl_Position = vec4(aPos, 1.0);
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TexCoord = vec2(aTexCoord.x, aTexCoord.y);
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}
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);
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unsigned int vs = glCreateShader(GL_VERTEX_SHADER);
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glShaderSource(vs, 1, &vs_code, NULL);
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glCompileShader(vs);
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int success;
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char infolog[512];
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glGetShaderiv(vs, GL_COMPILE_STATUS, &success);
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if (!success) {
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glGetShaderInfoLog(vs, 512, NULL, infolog);
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printf("%s\n", infolog);
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}
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// fragment shader
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const GLchar *fs_code = "#version 330 core\n" CODE(
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out vec4 FragColor;
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in vec2 TexCoord;
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// texture samplers
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uniform sampler2D texture1;
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void main(void) {
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FragColor = texture(texture1, TexCoord);
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}
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);
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unsigned int fs = glCreateShader(GL_FRAGMENT_SHADER);
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glShaderSource(fs, 1, &fs_code, NULL);
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glCompileShader(fs);
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glGetShaderiv(fs, GL_COMPILE_STATUS, &success);
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if (!success) {
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glGetShaderInfoLog(fs, 512, NULL, infolog);
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printf("%s\n", infolog);
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}
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// create program
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int program = g_program = glCreateProgram();
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glAttachShader(program, vs);
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glAttachShader(program, fs);
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glLinkProgram(program);
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glGetProgramiv(program, GL_LINK_STATUS, &success);
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if (!success) {
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glGetProgramInfoLog(program, 512, NULL, infolog);
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printf("%s\n", infolog);
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}
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if (g_config.shader)
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g_glsl_shader = GlslShader_CreateFromFile(g_config.shader);
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return true;
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}
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static void OpenGLRenderer_Destroy(void) {
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}
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static void OpenGLRenderer_BeginDraw(int width, int height, uint8 **pixels, int *pitch) {
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int size = width * height;
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if (size > g_screen_buffer_size) {
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g_screen_buffer_size = size;
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free(g_screen_buffer);
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g_screen_buffer = (uint8*)malloc(size * 4);
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}
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g_draw_width = width;
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g_draw_height = height;
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*pixels = g_screen_buffer;
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*pitch = width * 4;
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}
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static void OpenGLRenderer_EndDraw(void) {
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int drawable_width, drawable_height;
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SDL_GL_GetDrawableSize(g_window, &drawable_width, &drawable_height);
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int viewport_width = drawable_width, viewport_height = drawable_height;
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if (!g_config.ignore_aspect_ratio) {
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if (viewport_width * g_draw_height < viewport_height * g_draw_width)
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viewport_height = viewport_width * g_draw_height / g_draw_width; // limit height
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else
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viewport_width = viewport_height * g_draw_width / g_draw_height; // limit width
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}
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int viewport_x = (drawable_width - viewport_width) >> 1;
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int viewport_y = (viewport_height - viewport_height) >> 1;
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glBindTexture(GL_TEXTURE_2D, g_texture.gl_texture);
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if (g_draw_width == g_texture.width && g_draw_height == g_texture.height) {
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glTexSubImage2D(GL_TEXTURE_2D, 0, 0, 0, g_draw_width, g_draw_height, GL_BGRA, GL_UNSIGNED_INT_8_8_8_8_REV, g_screen_buffer);
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} else {
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g_texture.width = g_draw_width;
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g_texture.height = g_draw_height;
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glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, g_draw_width, g_draw_height, 0, GL_BGRA, GL_UNSIGNED_INT_8_8_8_8_REV, g_screen_buffer);
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}
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glClearColor(0.0f, 0.0f, 0.0f, 1.0f);
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glClear(GL_COLOR_BUFFER_BIT);
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if (g_glsl_shader == NULL) {
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glViewport(viewport_x, viewport_y, viewport_width, viewport_height);
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glUseProgram(g_program);
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int filter = g_config.linear_filtering ? GL_LINEAR : GL_NEAREST;
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glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, filter);
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glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, filter);
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glBindVertexArray(g_VAO);
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glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);
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} else {
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GlslShader_Render(g_glsl_shader, &g_texture, viewport_x, viewport_y, viewport_width, viewport_height);
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}
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SDL_GL_SwapWindow(g_window);
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}
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static const struct RendererFuncs kOpenGLRendererFuncs = {
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&OpenGLRenderer_Init,
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&OpenGLRenderer_Destroy,
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&OpenGLRenderer_BeginDraw,
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&OpenGLRenderer_EndDraw,
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};
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void OpenGLRenderer_Create(struct RendererFuncs *funcs) {
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SDL_GL_SetAttribute(SDL_GL_CONTEXT_PROFILE_MASK, SDL_GL_CONTEXT_PROFILE_CORE);
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SDL_GL_SetAttribute(SDL_GL_CONTEXT_MAJOR_VERSION, 3);
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SDL_GL_SetAttribute(SDL_GL_CONTEXT_MINOR_VERSION, 3);
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*funcs = kOpenGLRendererFuncs;
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}
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