1 files changed, 82 insertions, 0 deletions
diff --git a/src/renderer/backends/backend_opengl.c b/src/renderer/backends/backend_opengl.c
index 6022dbf..ea6cb00 100644
--- a/src/renderer/backends/backend_opengl.c
+++ b/src/renderer/backends/backend_opengl.c
@@ -2,6 +2,7 @@
 #define CEL_PLATFORM_LINUX
 
 #include "defines.h"
+#include "file.h"
 #include "log.h"
 #include "maths_types.h"
 #include "render_types.h"
@@ -59,4 +60,85 @@ void clear_screen(vec3 colour) {
   glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
 }
 
+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
 \ No newline at end of file