textures working on web, separation of vertex and index buffers (actually matters)

apps/templates/c/game.c

@@ -18,13 +18,9 @@ void game_tick(void) {
     struct state *state = ctx.udata;
     ++state->counter;
 
-    m_sprite("nothing!",
+    m_sprite("twn.png",
-            (Rect) {
+            (Rect) { .w = 128, .h = 64, },
-                .x = 0,
+            m_opt(stretch, true)
-                .y = 0,
-                .w = 32,
-                .h = 32,
-            }
     );
 }
 

src/rendering/twn_draw_c.h

@@ -39,12 +39,18 @@ enum {
 
 
 typedef uint32_t VertexBuffer;
+typedef uint32_t IndexBuffer;
 
 typedef struct VertexBufferBuilder {
     size_t size;
     void *base;
 } VertexBufferBuilder;
 
+typedef struct IndexBufferBuilder {
+    size_t size;
+    void *base;
+} IndexBufferBuilder;
+
 
 typedef struct SpritePrimitive {
     Rect rect;
@@ -268,19 +274,19 @@ void text_cache_reset_arena(TextCache *cache);
 /* vertex buffer */
 
 VertexBuffer create_vertex_buffer(void);
-
 void restart_scratch_vertex_arrays(void);
-
 VertexBuffer get_scratch_vertex_array(void);
-
 void delete_vertex_buffer(VertexBuffer buffer);
-
 void specify_vertex_buffer(VertexBuffer buffer, void const *data, size_t bytes);
-
 VertexBufferBuilder build_vertex_buffer(VertexBuffer buffer, size_t bytes);
-
 void finish_vertex_builder(VertexBufferBuilder *builder);
 
+IndexBuffer create_index_buffer(void);
+void delete_index_buffer(IndexBuffer buffer);
+void specify_index_buffer(IndexBuffer buffer, void const *data, size_t bytes);
+IndexBufferBuilder build_index_buffer(IndexBuffer buffer, size_t bytes);
+void finish_index_builder(IndexBufferBuilder *builder);
+
 /* 2d */
 
 /* fills two existing arrays with the geometry data of a circle */
@@ -304,9 +310,8 @@ struct QuadBatch collect_rect_batch(const Primitive2D primitives[], size_t len);
 void render_sprite_batch(const Primitive2D primitives[], struct QuadBatch batch);
 void render_rect_batch(const Primitive2D primitives[], struct QuadBatch batch);
 
-VertexBuffer get_quad_element_buffer(void);
+IndexBuffer get_quad_element_buffer(void);
-
+IndexBuffer get_circle_element_buffer(void);
-VertexBuffer get_circle_element_buffer(void);
 
 void render_circle(const CirclePrimitive *circle);
 

src/rendering/twn_gl_15_rendering.c

@@ -50,8 +50,9 @@ bool render_init(void) {
 
     log_info("OpenGL context: %s\n", glGetString(GL_VERSION));
 
-#ifndef __EMSCRIPTEN__
     glHint(GL_TEXTURE_COMPRESSION_HINT, GL_NICEST);
+
+#ifndef __EMSCRIPTEN__
     glHint(GL_GENERATE_MIPMAP_HINT, GL_NICEST);
     glHint(GL_FOG_HINT, GL_FASTEST);
 
@@ -196,59 +197,79 @@ static void finally_use_2d_pipeline(void) {
     pipeline_last_used = PIPELINE_2D;
 }
 
+
+static void setup_ghostly_texture_mode(void) {
+#ifndef __EMSCRIPTEN__
+    static GLuint list = 0;
+    if (!list) {
+        list = glGenLists(1);
+        glNewList(list, GL_COMPILE);
+#endif
+        glEnable(GL_BLEND);
+        glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
+        glDepthFunc(GL_LESS);
+        glDepthMask(GL_FALSE);
+        glDisable(GL_ALPHA_TEST);
+#ifndef __EMSCRIPTEN__
+        glEndList();
+    }
+    glCallList(list);
+#endif
+}
+
+
+static void setup_seethrough_texture_mode(void) {
+#ifndef __EMSCRIPTEN__
+    static GLuint list = 0;
+    if (!list) {
+        list = glGenLists(1);
+        glNewList(list, GL_COMPILE);
+#endif
+        glDisable(GL_BLEND);
+        glDepthFunc(GL_LESS);
+        glDepthMask(GL_TRUE);
+        glEnable(GL_ALPHA_TEST);
+        glAlphaFunc(GL_EQUAL, 1.0f);
+#ifndef __EMSCRIPTEN__
+        glEndList();
+    }
+    glCallList(list);
+#endif
+}
+
+
+static void setup_opaque_texture_mode(void) {
+#ifndef __EMSCRIPTEN__
+    static GLuint list = 0;
+    if (!list) {
+        list = glGenLists(1);
+        glNewList(list, GL_COMPILE);
+#endif
+        glDisable(GL_BLEND);
+        glDepthFunc(GL_LESS);
+        glDepthMask(GL_TRUE);
+        glDisable(GL_ALPHA_TEST);
+#ifndef __EMSCRIPTEN__
+        glEndList();
+    }
+    glCallList(list);
+#endif
+}
+
+
 /* TODO: ensure we minimize depth func switching to enable Hi-Z (hierarchical depth) optimizations */
 static void finally_use_texture_mode(TextureMode mode) {
     if (texture_mode_last_used == mode)
         return;
 
-#ifndef __EMSCRIPTEN__
-    static GLuint lists = 0;
-    if (!lists) {
-        lists = glGenLists(3);
-
-        /* ghostly */
-        glNewList(lists + 0, GL_COMPILE); {
-#endif
-            glEnable(GL_BLEND);
-            glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
-            glDepthFunc(GL_LESS);
-            glDepthMask(GL_FALSE);
-            glDisable(GL_ALPHA_TEST);
-#ifndef __EMSCRIPTEN__
-        } glEndList();
-
-        /* seethrough */
-        glNewList(lists + 1, GL_COMPILE); {
-#endif
-            glDisable(GL_BLEND);
-            glDepthFunc(GL_LESS);
-            glDepthMask(GL_TRUE);
-            glEnable(GL_ALPHA_TEST);
-            glAlphaFunc(GL_EQUAL, 1.0f);
-#ifndef __EMSCRIPTEN__
-        } glEndList();
-
-        /* opaque */
-        glNewList(lists + 2, GL_COMPILE); {
-#endif
-            glDisable(GL_BLEND);
-            glDepthFunc(GL_LESS);
-            glDepthMask(GL_TRUE);
-            glDisable(GL_ALPHA_TEST);
-#ifndef __EMSCRIPTEN__
-        } glEndList();
-    }
-
     if (mode == TEXTURE_MODE_GHOSTLY) {
-        glCallList(lists + 0);
+        setup_ghostly_texture_mode();
     } else if (mode == TEXTURE_MODE_SEETHROUGH) {
-        glCallList(lists + 1);
+        setup_seethrough_texture_mode();
     } else {
-        glCallList(lists + 2);
+        setup_opaque_texture_mode();
     }
 
-#endif
-
     texture_mode_last_used = mode;
 }
 
@@ -287,6 +308,40 @@ void finish_vertex_builder(VertexBufferBuilder *builder) {
 }
 
 
+IndexBufferBuilder build_index_buffer(IndexBuffer buffer, size_t bytes) {
+    SDL_assert(bytes != 0);
+    glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, buffer);
+    glBufferData(GL_ELEMENT_ARRAY_BUFFER, bytes, NULL, GL_STREAM_DRAW);
+#ifndef __EMSCRIPTEN__
+    void *mapping = glMapBuffer(GL_ELEMENT_ARRAY_BUFFER, GL_WRITE_ONLY);
+#else
+    void *mapping = SDL_malloc(bytes);
+#endif
+    if (!mapping)
+        CRY("build_vertex_buffer", "Error mapping a vertex array buffer");
+
+    return (IndexBufferBuilder) {
+        .base = mapping,
+        .size = bytes,
+    };
+}
+
+
+void finish_index_builder(IndexBufferBuilder *builder) {
+#ifndef __EMSCRIPTEN__
+    if (!glUnmapBuffer(GL_ELEMENT_ARRAY_BUFFER))
+        CRY("finish_vertex_builder", "Error unmapping a vertex array buffer");
+#else
+    glBufferData(GL_ELEMENT_ARRAY_BUFFER, builder->size, builder->base, GL_STREAM_DRAW);
+    SDL_free(builder->base);
+#endif
+    glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, 0);
+
+    builder->base = 0;
+    builder->size = 0;
+}
+
+
 static void load_cubemap_side(const char *path, GLenum target) {
     SDL_Surface *surface = textures_load_surface(path);
     /* TODO: sanity check whether all of them have same dimensions? */

src/rendering/twn_gl_any_rendering.c

@@ -29,6 +29,18 @@ void delete_vertex_buffer(VertexBuffer buffer) {
 }
 
 
+IndexBuffer create_index_buffer(void) {
+    GLuint result;
+    glGenBuffers(1, &result);
+    return result;
+}
+
+
+void delete_index_buffer(IndexBuffer buffer) {
+    glDeleteBuffers(1, &buffer);
+}
+
+
 void specify_vertex_buffer(VertexBuffer buffer, void const *data, size_t bytes) {
     glBindBuffer(GL_ARRAY_BUFFER, buffer);
     glBufferData(GL_ARRAY_BUFFER, bytes, data, GL_STREAM_DRAW);
@@ -36,14 +48,21 @@ void specify_vertex_buffer(VertexBuffer buffer, void const *data, size_t bytes)
 }
 
 
-VertexBuffer get_quad_element_buffer(void) {
+void specify_index_buffer(IndexBuffer buffer, void const *data, size_t bytes) {
-    static VertexBuffer buffer = 0;
+    glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, buffer);
+    glBufferData(GL_ELEMENT_ARRAY_BUFFER, bytes, data, GL_STATIC_DRAW);
+    glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, 0);
+}
+
+
+IndexBuffer get_quad_element_buffer(void) {
+    static IndexBuffer buffer = 0;
 
     /* it's only generated once at runtime */
     /* TODO: use builder interface, not direct calls (glMapBuffer isn't portable) */
     if (buffer == 0) {
-        buffer = create_vertex_buffer();
+        buffer = create_index_buffer();
-        VertexBufferBuilder builder = build_vertex_buffer(buffer, sizeof (GLshort) * QUAD_ELEMENT_BUFFER_LENGTH * 6 );
+        IndexBufferBuilder builder = build_index_buffer(buffer, sizeof (GLshort) * QUAD_ELEMENT_BUFFER_LENGTH * 6 );
 
         for (size_t i = 0; i < QUAD_ELEMENT_BUFFER_LENGTH; ++i) {
             ((GLshort *)builder.base)[i * 6 + 0] = (GLshort)(i * 4 + 0);
@@ -54,7 +73,7 @@ VertexBuffer get_quad_element_buffer(void) {
             ((GLshort *)builder.base)[i * 6 + 5] = (GLshort)(i * 4 + 0);
         }
 
-        finish_vertex_builder(&builder);
+        finish_index_builder(&builder);
     }
 
     SDL_assert_always(buffer);
@@ -63,12 +82,12 @@ VertexBuffer get_quad_element_buffer(void) {
 }
 
 
-VertexBuffer get_circle_element_buffer(void) {
+IndexBuffer get_circle_element_buffer(void) {
-    static VertexBuffer buffer = 0;
+    static IndexBuffer buffer = 0;
 
     if (buffer == 0) {
-        buffer = create_vertex_buffer();
+        buffer = create_index_buffer();
-        VertexBufferBuilder builder = build_vertex_buffer(buffer, sizeof (GLshort) * (CIRCLE_VERTICES_MAX - 2) * 3);
+        IndexBufferBuilder builder = build_index_buffer(buffer, sizeof (GLshort) * (CIRCLE_VERTICES_MAX - 2) * 3);
 
         for (size_t i = 1; i < CIRCLE_VERTICES_MAX - 1; ++i) {
             /* first one is center point index, always zero */
@@ -79,7 +98,7 @@ VertexBuffer get_circle_element_buffer(void) {
             ((GLshort *)builder.base)[(i - 1) * 3 + 2] = (GLshort)i + 1;
         }
 
-        finish_vertex_builder(&builder);
+        finish_index_builder(&builder);
     }
 
     SDL_assert_always(buffer);
@@ -128,7 +147,11 @@ GPUTexture create_gpu_texture(TextureFilter filter, bool generate_mipmaps, int c
     SDL_assert(width > 0 && height > 0);
     SDL_assert(channels > 0 && channels <= 4);
 
+#ifndef __EMSCRIPTEN__
     glTexParameteri(GL_TEXTURE_2D, GL_GENERATE_MIPMAP, (GLboolean)generate_mipmaps);
+#else
+    (void)generate_mipmaps;
+#endif
 
     if (filter == TEXTURE_FILTER_NEAREAST) {
         glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);

src/twn_loop.c

@@ -881,7 +881,7 @@ int enter_loop(int argc, char **argv) {
     profile_end("startup");
 
 #ifdef __EMSCRIPTEN__
-    emscripten_set_main_loop(main_loop, ctx.desired_frametime, true);
+    emscripten_set_main_loop(main_loop, 0, true);
 #else
     while (ctx.is_running)
         main_loop();