big rendering overhaul (cleaning and api abstraction)

src/rendering/twn_gl_any_rendering.c

@@ -1,6 +1,6 @@
-#include "twn_gl_any_rendering_c.h"
-#include "twn_draw_c.h"
 #include "twn_engine_context_c.h"
+#include "twn_util_c.h"
+#include "twn_draw_c.h"
 
 #include <stb_ds.h>
 
@@ -120,3 +120,85 @@ GLuint get_scratch_vertex_array(void) {
     (*used)++;
     return (*current_scratch_vertex_array)[*used - 1];
 }
+
+
+GPUTexture create_gpu_texture(TextureFilter filter, bool generate_mipmaps) {
+    GLuint texture;
+    glGenTextures(1, &texture);
+    glBindTexture(GL_TEXTURE_2D, texture);
+
+#if !defined(EMSCRIPTEN)
+    glTexParameteri(GL_TEXTURE_2D, GL_GENERATE_MIPMAP, (GLboolean)generate_mipmaps);
+#else
+    if (generate_mipmaps)
+        glGenerateMipmap(GL_TEXTURE_2D);
+#endif
+
+    if (filter == TEXTURE_FILTER_NEAREAST) {
+        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
+        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
+    } else if (filter == TEXTURE_FILTER_LINEAR) {
+        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
+        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
+    }
+
+    glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
+    glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
+
+#if !defined(EMSCRIPTEN)
+    glTexEnvi(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE);
+#endif
+
+    glBindTexture(GL_TEXTURE_2D, 0);
+    return texture;
+}
+
+
+void delete_gpu_texture(GPUTexture texture) {
+    glDeleteTextures(1, &texture);
+}
+
+
+void upload_gpu_texture(GPUTexture texture, void *pixels, int channels, int width, int height) {
+    glBindTexture(GL_TEXTURE_2D, texture);
+
+    int format_internal, format;
+    if (channels == 4) {
+        #ifdef EMSCRIPTEN
+        format_internal = GL_RGBA;
+        #else
+        format_internal = GL_RGBA8;
+        #endif
+        format = GL_RGBA;
+    } else if (channels == 3) {
+        #ifdef EMSCRIPTEN
+        format_internal = GL_RGBA;
+        #else
+        format_internal = GL_RGBA8;
+        #endif
+        format = GL_RGB;
+    } else if (channels == 1) {
+        format_internal = GL_ALPHA;
+        format = GL_ALPHA;
+    } else {
+        CRY("upload_gpu_texture", "Unsupported channel count");
+        return;
+    }
+
+    glTexImage2D(GL_TEXTURE_2D,
+                 0,
+                 format_internal,
+                 width,
+                 height,
+                 0,
+                 format,
+                 GL_UNSIGNED_BYTE,
+                 pixels);
+
+    glBindTexture(GL_TEXTURE_2D, 0);
+}
+
+
+void bind_gpu_texture(GPUTexture texture) {
+    glBindTexture(GL_TEXTURE_2D, texture);
+}