multiple files

renderer.c

@@ -0,0 +1,171 @@
+#define GL_GLEXT_PROTOTYPES
+#include <stdio.h>
+#include <GL/gl.h>
+#include <stdlib.h>
+#include "renderer.h"
+
+void checkGlError() {
+    //const char *err = SDL_GetError();
+    //if (*err != 0) {
+    //    printf("OpenGL error: %s", err);
+    //}
+}
+
+/// returns 0 if failed.
+GLuint compile_shader(GLuint type, const char *src) {
+    GLuint id = glCreateShader(type);
+    glShaderSource(id, 1, &src, 0);
+    glCompileShader(id);
+
+    int result;
+    glGetShaderiv(id, GL_COMPILE_STATUS, &result);
+    if (result == GL_FALSE) {
+        int length;
+        glGetShaderiv(id, GL_INFO_LOG_LENGTH, &result);
+        char *message = alloca(length * sizeof(char));
+        glGetShaderInfoLog(id, length, &length, message);
+        printf("failed to compile %s shader\n", type == GL_VERTEX_SHADER ? "vertex" : "fragment");
+        printf("%s\n", message);
+        glDeleteShader(id);
+        return 0;
+    }
+
+    return id;
+}
+
+const char *vertex_shader_src =
+//"attribute vec4 vPosition; \n"
+//"void main() \n"
+//"{ \n"
+//" gl_Position = vPosition; \n"
+//"} \n";
+"#version 320 es\n"
+"\n"
+"layout(location = 0) in vec2 aPos;\n"
+"\n"
+"void main() {\n"
+"    gl_Position = vec4(aPos, 0.0, 1.0);\n"
+"}\n";
+
+/// returns 0 if failed.
+GLuint create_shader(const char *fragment_src) {
+    GLuint program = glCreateProgram();
+    GLuint vertex_shader = compile_shader(GL_VERTEX_SHADER, vertex_shader_src);
+    GLuint fragment_shader = compile_shader(GL_FRAGMENT_SHADER, fragment_src);
+    if (!((fragment_shader == 0) || (vertex_shader == 0))) {
+        glAttachShader(program, vertex_shader);
+        glAttachShader(program, fragment_shader);
+        glLinkProgram(program);
+        glValidateProgram(program);
+        glDeleteShader(vertex_shader);
+        glDeleteShader(fragment_shader);
+        return program;
+    } else {
+        return 0;
+    }
+}
+
+GLuint load_shader(const char *path) {
+    FILE *handle = fopen(path, "r");
+    fseek(handle, 0L, SEEK_END);
+    long length = ftell(handle);
+    fseek(handle, 0L, SEEK_SET);
+    char *string = malloc(length * sizeof(char));
+    if (!fread(string, sizeof(char), length, handle)) {
+        printf("failed to read shader file");
+        exit(1);
+    }
+    fclose(handle);
+
+    GLuint shader = create_shader(string);
+
+    //if (shader == 0) {
+    //    // print file
+    //    int line_count = 1;
+    //    printf("%i\t", line_count);
+    //    line_count++;
+    //    for (int i = 0; i < length; i++) {
+    //        printf("%c", string[i]);
+    //        if (string[i] == '\n') {
+    //            printf("%i\t", line_count);
+    //            line_count++;
+    //        }
+    //    }
+    //    printf("\n");
+    //}
+
+    free(string);
+    return shader;
+}
+
+Renderer new_renderer() {
+    const char *version_str = (const char *)glGetString(GL_VERSION);
+    const char *renderer_str = (const char *)glGetString(GL_RENDERER);
+    printf("GL_VERSION: %s\n", version_str);
+    printf("GL_RENDERER: %s\n", renderer_str);
+
+    glEnable(GL_DEPTH_TEST);
+
+    GLuint shader = load_shader("fragment.glsl"); //create_shader(fragment_shader_source);
+
+    // buffers
+    // Load the vertex data
+    GLfloat vertices[] = {
+        -1.0, 1.0,
+        -1.0, -1.0,
+        1.0, -1.0,
+
+        1.0, -1.0,
+        1.0, 1.0,
+        -1.0, 1.0,
+    };
+    GLuint vao, vbo;
+    glGenVertexArrays(1, &vao);
+    glBindVertexArray(vao);
+    glGenBuffers(1, &vbo);
+    glBindBuffer(GL_ARRAY_BUFFER, vbo);
+    glBufferData(GL_ARRAY_BUFFER,
+                 sizeof(vertices),
+                 vertices,
+                 GL_STATIC_DRAW);
+    
+    glEnableVertexAttribArray(0);
+    glVertexAttribPointer(
+        0,              // location
+        2,              // vec2
+        GL_FLOAT,
+        GL_FALSE,
+        0,
+        (void *)0
+    );
+
+    Renderer renderer = { shader, vao };
+    return renderer;
+}
+
+void render(Renderer *state, int w, int h, double time) {
+    checkGlError();
+
+    // Rendorrrr
+    glViewport(0, 0, w, h);
+
+    glClearColor(0.1f, 0.1f, 0.1f, 1.0f);  // Dark gray background
+    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
+
+    // Shader parameters.
+    glUseProgram(state->shader);
+
+    int uniform_WindowSize = glGetUniformLocation(state->shader, "WindowSize");
+    glUniform2f(uniform_WindowSize, w, h);
+
+    int uniform_time = glGetUniformLocation(state->shader, "time");
+    glUniform1f(uniform_time, (float)time);
+
+    //glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 0, vVertices);
+    //glEnableVertexAttribArray(0);
+    //glDrawArrays(GL_TRIANGLES, 0, 6);
+
+    glBindVertexArray(state->vao);
+    glDrawArrays(GL_TRIANGLES, 0, 6);
+}
+