SameBoy/SDL/shader.c

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#include <stdio.h>
#include <string.h>
#include "shader.h"
#include "utils.h"
static const char *vertex_shader = "\n\
#version 150 \n\
in vec4 aPosition;\n\
void main(void) {\n\
gl_Position = aPosition;\n\
}\n\
";
static GLuint create_shader(const char *source, GLenum type)
{
// Create the shader object
GLuint shader = glCreateShader(type);
// Load the shader source
glShaderSource(shader, 1, &source, 0);
// Compile the shader
glCompileShader(shader);
// Check for errors
GLint status = 0;
glGetShaderiv(shader, GL_COMPILE_STATUS, &status);
if (status == GL_FALSE) {
GLchar messages[1024];
glGetShaderInfoLog(shader, sizeof(messages), 0, &messages[0]);
fprintf(stderr, "GLSL Shader Error: %s", messages);
}
return shader;
}
static GLuint create_program(const char *vsh, const char *fsh)
{
// Build shaders
GLuint vertex_shader = create_shader(vsh, GL_VERTEX_SHADER);
GLuint fragment_shader = create_shader(fsh, GL_FRAGMENT_SHADER);
// Create program
GLuint program = glCreateProgram();
// Attach shaders
glAttachShader(program, vertex_shader);
glAttachShader(program, fragment_shader);
// Link program
glLinkProgram(program);
// Check for errors
GLint status;
glGetProgramiv(program, GL_LINK_STATUS, &status);
if (status == GL_FALSE) {
GLchar messages[1024];
glGetProgramInfoLog(program, sizeof(messages), 0, &messages[0]);
fprintf(stderr, "GLSL Program Error: %s", messages);
}
// Delete shaders
glDeleteShader(vertex_shader);
glDeleteShader(fragment_shader);
return program;
}
bool init_shader_with_name(shader_t *shader, const char *name)
{
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GLint major = 0, minor = 0;
glGetIntegerv(GL_MAJOR_VERSION, &major);
glGetIntegerv(GL_MINOR_VERSION, &minor);
if (major * 0x100 + minor < 0x302) {
return false;
}
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static char master_shader_code[0x801] = {0,};
static char shader_code[0x10001] = {0,};
static char final_shader_code[0x10801] = {0,};
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static signed long filter_token_location = 0;
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if (!master_shader_code[0]) {
FILE *master_shader_f = fopen(executable_relative_path("Shaders/MasterShader.fsh"), "r");
if (!master_shader_f) return false;
fread(master_shader_code, 1, sizeof(master_shader_code) - 1, master_shader_f);
fclose(master_shader_f);
filter_token_location = strstr(master_shader_code, "{filter}") - master_shader_code;
if (filter_token_location < 0) {
master_shader_code[0] = 0;
return false;
}
}
char shader_path[1024];
sprintf(shader_path, "Shaders/%s.fsh", name);
FILE *shader_f = fopen(executable_relative_path(shader_path), "r");
if (!shader_f) return false;
memset(shader_code, 0, sizeof(shader_code));
fread(shader_code, 1, sizeof(shader_code) - 1, shader_f);
fclose(shader_f);
memset(final_shader_code, 0, sizeof(final_shader_code));
memcpy(final_shader_code, master_shader_code, filter_token_location);
strcpy(final_shader_code + filter_token_location, shader_code);
strcat(final_shader_code + filter_token_location,
master_shader_code + filter_token_location + sizeof("{filter}") - 1);
shader->program = create_program(vertex_shader, final_shader_code);
// Attributes
shader->position_attribute = glGetAttribLocation(shader->program, "aPosition");
// Uniforms
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shader->resolution_uniform = glGetUniformLocation(shader->program, "output_resolution");
shader->origin_uniform = glGetUniformLocation(shader->program, "origin");
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glGenTextures(1, &shader->texture);
glBindTexture(GL_TEXTURE_2D, shader->texture);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_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);
glBindTexture(GL_TEXTURE_2D, 0);
shader->texture_uniform = glGetUniformLocation(shader->program, "image");
glGenTextures(1, &shader->previous_texture);
glBindTexture(GL_TEXTURE_2D, shader->previous_texture);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_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);
glBindTexture(GL_TEXTURE_2D, 0);
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shader->previous_texture_uniform = glGetUniformLocation(shader->program, "previous_image");
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shader->mix_previous_uniform = glGetUniformLocation(shader->program, "mix_previous");
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// Program
glUseProgram(shader->program);
GLuint vao;
glGenVertexArrays(1, &vao);
glBindVertexArray(vao);
GLuint vbo;
glGenBuffers(1, &vbo);
// Attributes
static GLfloat const quad[16] = {
-1.f, -1.f, 0, 1,
-1.f, +1.f, 0, 1,
+1.f, -1.f, 0, 1,
+1.f, +1.f, 0, 1,
};
glBindBuffer(GL_ARRAY_BUFFER, vbo);
glBufferData(GL_ARRAY_BUFFER, sizeof(quad), quad, GL_STATIC_DRAW);
glEnableVertexAttribArray(shader->position_attribute);
glVertexAttribPointer(shader->position_attribute, 4, GL_FLOAT, GL_FALSE, 0, 0);
return true;
}
void render_bitmap_with_shader(shader_t *shader, void *bitmap, void *previous,unsigned x, unsigned y, unsigned w, unsigned h)
{
glUseProgram(shader->program);
glUniform2f(shader->origin_uniform, x, y);
glUniform2f(shader->resolution_uniform, w, h);
glActiveTexture(GL_TEXTURE0);
glBindTexture(GL_TEXTURE_2D, shader->texture);
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, 160, 144, 0, GL_RGBA, GL_UNSIGNED_BYTE, bitmap);
glUniform1i(shader->texture_uniform, 0);
glUniform1i(shader->mix_previous_uniform, previous != NULL);
if (previous) {
glActiveTexture(GL_TEXTURE1);
glBindTexture(GL_TEXTURE_2D, shader->previous_texture);
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, 160, 144, 0, GL_RGBA, GL_UNSIGNED_BYTE, previous);
glUniform1i(shader->previous_texture_uniform, 1);
}
glBindFragDataLocation(shader->program, 0, "frag_color");
glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);
}
void free_shader(shader_t *shader)
{
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GLint major = 0, minor = 0;
glGetIntegerv(GL_MAJOR_VERSION, &major);
glGetIntegerv(GL_MINOR_VERSION, &minor);
if (major * 0x100 + minor < 0x302) {
return;
}
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glDeleteProgram(shader->program);
glDeleteTextures(1, &shader->texture);
glDeleteTextures(1, &shader->previous_texture);
}