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#include <stdlib.h>
#define CEL_PLATFORM_LINUX
#include "defines.h"
#include "file.h"
#include "log.h"
#include "maths_types.h"
#include "render_types.h"
#if CEL_REND_BACKEND_OPENGL
#include <glad/glad.h>
#include <glfw3.h>
/** @brief Internal backend state */
typedef struct opengl_state {
} opengl_state;
bool gfx_backend_init(renderer *ren) {
INFO("loading OpenGL backend");
// glfwInit(); // Already handled in `renderer_init`
glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 4);
glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 1);
glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);
glfwWindowHint(GLFW_OPENGL_FORWARD_COMPAT, GL_TRUE);
// glad: load all OpenGL function pointers
if (!gladLoadGLLoader((GLADloadproc)glfwGetProcAddress)) {
ERROR("Failed to initialise GLAD \n");
return false;
}
glEnable(GL_DEPTH_TEST);
opengl_state *internal = malloc(sizeof(opengl_state));
ren->backend_state = (void *)internal;
return true;
}
void gfx_backend_shutdown(renderer *ren) {}
void uniform_vec3f(u32 program_id, const char *uniform_name, vec3 *value) {
glUniform3fv(glGetUniformLocation(program_id, uniform_name), 1, &value->x);
}
void uniform_f32(u32 program_id, const char *uniform_name, f32 value) {
glUniform1f(glGetUniformLocation(program_id, uniform_name), value);
}
void uniform_i32(u32 program_id, const char *uniform_name, i32 value) {
glUniform1i(glGetUniformLocation(program_id, uniform_name), value);
}
void uniform_mat4f(u32 program_id, const char *uniform_name, mat4 *value) {
glUniformMatrix4fv(glGetUniformLocation(program_id, uniform_name), 1, GL_FALSE, value->data);
}
void clear_screen(vec3 colour) {
glClearColor(colour.x, colour.y, colour.z, 1.0f);
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
}
void texture_data_upload(texture* tex) {
printf("Texture name %s\n", tex->name);
TRACE("Upload texture data");
u32 texture_id;
glGenTextures(1, &texture_id);
glBindTexture(GL_TEXTURE_2D, texture_id);
tex->texture_id = texture_id;
// set the texture wrapping parameters
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S,
GL_REPEAT); // set texture wrapping to GL_REPEAT (default wrapping method)
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
// set texture filtering parameters
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR_MIPMAP_LINEAR);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, tex->width, tex->height, 0, tex->channel_type,
GL_UNSIGNED_BYTE, tex->image_data);
glGenerateMipmap(GL_TEXTURE_2D);
DEBUG("Freeing texture image data after uploading to GPU");
// stbi_image_free(tex->image_data); // data is on gpu now so we dont need it around
}
void bind_texture(shader s, texture *tex, u32 slot) {
// printf("bind texture slot %d with texture id %d \n", slot, tex->texture_id);
glActiveTexture(GL_TEXTURE0 + slot);
glBindTexture(GL_TEXTURE_2D, tex->texture_id);
}
void bind_mesh_vertex_buffer(void *_backend, mesh *mesh) { glBindVertexArray(mesh->vao); }
static inline GLenum to_gl_prim_topology(enum cel_primitive_topology primitive) {
switch (primitive) {
case CEL_PRIMITIVE_TOPOLOGY_TRIANGLE:
return GL_TRIANGLES;
case CEL_PRIMITIVE_TOPOLOGY_POINT:
case CEL_PRIMITIVE_TOPOLOGY_LINE:
case CEL_PRIMITIVE_TOPOLOGY_LINE_STRIP:
case CEL_PRIMITIVE_TOPOLOGY_TRIANGLE_STRIP:
case CEL_PRIMITIVE_TOPOLOGY_COUNT:
break;
}
}
void draw_primitives(cel_primitive_topology primitive, u32 start_index, u32 count) {
u32 gl_primitive = to_gl_prim_topology(primitive);
glDrawArrays(gl_primitive, start_index, count);
}
shader shader_create_separate(const char *vert_shader, const char *frag_shader) {
INFO("Load shaders at %s and %s", vert_shader, frag_shader);
int success;
char info_log[512];
u32 vertex = glCreateShader(GL_VERTEX_SHADER);
const char *vertex_shader_src = string_from_file(vert_shader);
if (vertex_shader_src == NULL) {
ERROR("EXIT: couldnt load shader");
exit(-1);
}
glShaderSource(vertex, 1, &vertex_shader_src, NULL);
glCompileShader(vertex);
glGetShaderiv(vertex, GL_COMPILE_STATUS, &success);
if (!success) {
glGetShaderInfoLog(vertex, 512, NULL, info_log);
printf("%s\n", info_log);
ERROR("EXIT: vertex shader compilation failed");
exit(-1);
}
// fragment shader
u32 fragment = glCreateShader(GL_FRAGMENT_SHADER);
const char *fragment_shader_src = string_from_file(frag_shader);
if (fragment_shader_src == NULL) {
ERROR("EXIT: couldnt load shader");
exit(-1);
}
glShaderSource(fragment, 1, &fragment_shader_src, NULL);
glCompileShader(fragment);
glGetShaderiv(fragment, GL_COMPILE_STATUS, &success);
if (!success) {
glGetShaderInfoLog(fragment, 512, NULL, info_log);
printf("%s\n", info_log);
ERROR("EXIT: fragment shader compilation failed");
exit(-1);
}
u32 shader_prog;
shader_prog = glCreateProgram();
glAttachShader(shader_prog, vertex);
glAttachShader(shader_prog, fragment);
glLinkProgram(shader_prog);
glDeleteShader(vertex);
glDeleteShader(fragment);
free((char *)vertex_shader_src);
free((char *)fragment_shader_src);
shader s = { .program_id = shader_prog };
return s;
}
void set_shader(shader s) { glUseProgram(s.program_id); }
#endif
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