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#include "shader.c"
#include "shader.h"
#include "data/fragment_shader.h"
#include "data/vertex_shader.h"
/* [=]===^=[ setup_render_target ]================================================================^===[=] */
static void setup_render_target(void) {
glDeleteTextures(1, &state.texture);
glGenTextures(1, &state.texture);
glBindTexture(GL_TEXTURE_2D, state.texture);
glTexImage2D(GL_TEXTURE_2D, 0, GL_SRGB8_ALPHA8, state.render_width, state.render_height, 0, GL_RGBA, GL_UNSIGNED_INT_8_8_8_8, buffer);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
glBindTexture(GL_TEXTURE_2D, 0);
}
/* [=]===^=[ compile_shader ]==============================================================^===[=] */
static GLuint compile_shader(GLenum shader_type, const char *shader_source) {
GLuint shader = glCreateShader(shader_type);
glShaderSource(shader, 1, &shader_source, 0);
glCompileShader(shader);
GLint success;
GLchar info_log[512];
glGetShaderiv(shader, GL_COMPILE_STATUS, &success);
if(!success) {
glGetShaderInfoLog(shader, sizeof(info_log), 0, info_log);
DEBUG_PRINT("%s shader compilation failed:\n%s\n", (shader_type == GL_VERTEX_SHADER) ? "Vertex" : "Fragment", info_log);
}
return shader;
}
/* [=]===^=[ setup_opengl ]================================================================^===[=] */
static void opengl_setup(const char *vertex_shader_src, const char *fragment_shader_src) {
gl_loader();
glEnable(GL_FRAMEBUFFER_SRGB);
glDisable(GL_DEPTH_TEST);
glEnable(GL_BLEND);
glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
glDisable(GL_CULL_FACE);
// Shader setup
GLuint vertex_shader = compile_shader(GL_VERTEX_SHADER, vertex_shader_src);
GLuint fragment_shader = compile_shader(GL_FRAGMENT_SHADER, fragment_shader_src);
state.shader_program = glCreateProgram();
glAttachShader(state.shader_program, vertex_shader);
glAttachShader(state.shader_program, fragment_shader);
glBindAttribLocation(state.shader_program, 0, "position");
glBindAttribLocation(state.shader_program, 1, "texture_coord");
glLinkProgram(state.shader_program);
GLint success;
glGetProgramiv(state.shader_program, GL_LINK_STATUS, &success);
if(!success) {
char log[512];
glGetProgramInfoLog(state.shader_program, sizeof(log), NULL, log);
DEBUG_PRINT("Shader Linking Failed: %s\n", log);
}
glDeleteShader(vertex_shader);
glDeleteShader(fragment_shader);
glUseProgram(state.shader_program);
// Calculations for the shader.
state.contrast = 1.0f;
state.saturation = 0.3f;
state.brightness = 1.0f;
CrtsTone(state.tone_data, state.contrast, state.saturation, INPUT_THIN, INPUT_MASK); // NOTE(peter): Move this into the mainloop if change of contrast/saturation is added as an interactive thing.
// Retrieve shader uniforms
state.uniform_resolution = glGetUniformLocation(state.shader_program, "resolution");
state.uniform_src_image_size = glGetUniformLocation(state.shader_program, "src_image_size");
state.uniform_brightness = glGetUniformLocation(state.shader_program, "brightness");
state.uniform_tone = glGetUniformLocation(state.shader_program, "tone_data");
state.uniform_crt_emulation = glGetUniformLocation(state.shader_program, "crt_emulation");
state.uniform_sampler_location = glGetUniformLocation(state.shader_program, "iChannel0");
glGenVertexArrays(1, &state.vao);
glGenBuffers(1, &state.vbo);
glGenBuffers(1, &state.ebo);
glBindVertexArray(state.vao);
// Vertex data: Position (x, y) and Texture Coordinates (u, v)
const float vertices[] = {
-1.0f, -1.0f, 0.0f, 0.0f, // Bottom-left
1.0f, -1.0f, 1.0f, 0.0f, // Bottom-right
1.0f, 1.0f, 1.0f, 1.0f, // Top-right
-1.0f, 1.0f, 0.0f, 1.0f // Top-left
};
static const unsigned int indices[] = { 0, 1, 2, 2, 3, 0 };
glBindBuffer(GL_ARRAY_BUFFER, state.vbo);
glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW);
glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, state.ebo);
glBufferData(GL_ELEMENT_ARRAY_BUFFER, sizeof(indices), indices, GL_STATIC_DRAW);
glVertexAttribPointer(0, 2, GL_FLOAT, GL_FALSE, 4 * sizeof(float), (void*)0); // Position
glVertexAttribPointer(1, 2, GL_FLOAT, GL_FALSE, 4 * sizeof(float), (void*)(2 * sizeof(float))); // Texture Coord
glEnableVertexAttribArray(0);
glEnableVertexAttribArray(1);
}
/* [=]===^=[ render_frame ]=================================================================^===[=] */
__attribute__((always_inline))
static inline void render_frame(void) {
glClearColor(.0f, 0.f, 0.f, 1.f);
glClear(GL_COLOR_BUFFER_BIT);
glUseProgram(state.shader_program);
glBindVertexArray(state.vao);
glBindBuffer(GL_ARRAY_BUFFER, state.vbo);
glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, state.ebo);
glActiveTexture(GL_TEXTURE0);
glBindTexture(GL_TEXTURE_2D, state.texture);
glTexSubImage2D(GL_TEXTURE_2D, 0, 0, 0, state.render_width, state.render_height, GL_RGBA, GL_UNSIGNED_INT_8_8_8_8, display_buffer);
glUniform2f(state.uniform_src_image_size, (float)state.render_width, (float)state.render_height);
glUniform2f(state.uniform_resolution, (float)state.viewport.w, (float)state.viewport.h);
glUniform1f(state.uniform_brightness, state.brightness);
glUniform4f(state.uniform_tone, state.tone_data[0], state.tone_data[1], state.tone_data[2], state.tone_data[3]);
glUniform1i(state.uniform_crt_emulation, state.toggle_crt_emulation);
glUniform1i(state.uniform_sampler_location, 0);
glViewport(state.viewport.x, state.viewport.y, state.viewport.w, state.viewport.h);
glEnableVertexAttribArray(0);
glEnableVertexAttribArray(1);
glDrawElements(GL_TRIANGLES, 6, GL_UNSIGNED_INT, 0);
}
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