work towards DeferredCommandDraw being universal, support for DeferredCommandDepthRange, rework of cirlce mesh (has a bug still), get_quad_element_buffer() now more general, as it should be with gl_any

src/rendering/twn_gl_any_rendering.c

@@ -33,40 +33,59 @@ void specify_vertex_buffer(VertexBuffer buffer, void const *data, size_t bytes)
 
 
 VertexBuffer get_quad_element_buffer(void) {
-    static GLuint buffer = 0;
+    static VertexBuffer buffer = 0;
 
     /* it's only generated once at runtime */
+    /* TODO: use builder interface, not direct calls (glMapBuffer isn't portable) */
     if (buffer == 0) {
-        glGenBuffers(1, &buffer);
-        glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, buffer);
-        glBufferData(GL_ELEMENT_ARRAY_BUFFER,
-                     QUAD_ELEMENT_BUFFER_LENGTH * 6 * sizeof(uint16_t),
-                     NULL,
-                     GL_STATIC_DRAW);
+        buffer = create_vertex_buffer();
+        VertexBufferBuilder builder = build_vertex_buffer(buffer, sizeof (GLshort) * QUAD_ELEMENT_BUFFER_LENGTH * 6 );
 
-        uint16_t *const indices = glMapBuffer(GL_ELEMENT_ARRAY_BUFFER,
-                                              GL_WRITE_ONLY);
-        if (!indices)
-            CRY("Quad indices generation", "glMapBuffer() failed");
+        for (size_t i = 0; i < QUAD_ELEMENT_BUFFER_LENGTH; ++i) {
+            GLshort indices[6];
+            indices[0] = (GLshort)(i * 4 + 0);
+            indices[1] = (GLshort)(i * 4 + 1);
+            indices[2] = (GLshort)(i * 4 + 2);
+            indices[3] = (GLshort)(i * 4 + 2);
+            indices[4] = (GLshort)(i * 4 + 3);
+            indices[5] = (GLshort)(i * 4 + 0);
 
-        for (uint16_t i = 0; i < QUAD_ELEMENT_BUFFER_LENGTH; ++i) {
-            indices[i * 6 + 0] = (uint16_t)(i * 4 + 0);
-            indices[i * 6 + 1] = (uint16_t)(i * 4 + 1);
-            indices[i * 6 + 2] = (uint16_t)(i * 4 + 2);
-            indices[i * 6 + 3] = (uint16_t)(i * 4 + 2);
-            indices[i * 6 + 4] = (uint16_t)(i * 4 + 3);
-            indices[i * 6 + 5] = (uint16_t)(i * 4 + 0);
+            push_to_vertex_buffer_builder(&builder, indices, sizeof indices);
         }
+    }
 
-        glUnmapBuffer(GL_ELEMENT_ARRAY_BUFFER);
-
-    } else
-        glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, buffer);
+    SDL_assert_always(buffer);
 
     return buffer;
 }
 
 
-void set_depth_range(double low, double high) {
-    glDepthRange(low, high);
+VertexBuffer get_circle_element_buffer(void) {
+    static VertexBuffer buffer = 0;
+
+    if (buffer == 0) {
+        buffer = create_vertex_buffer();
+        VertexBufferBuilder builder = build_vertex_buffer(buffer, sizeof (GLshort) * CIRCLE_ELEMENT_BUFFER_LENGTH);
+
+        for (size_t i = 1; i < CIRCLE_VERTICES_MAX; ++i) {
+            /* first one is center point index, always zero */
+            GLshort indices[3];
+
+            indices[0] = 0;
+
+            /* generated point index */
+            indices[1] = (GLshort)i;
+
+            size_t index = (i + 1) % (CIRCLE_VERTICES_MAX - 1);
+            if (index == 0) /* don't use center for outer ring */
+                index = (CIRCLE_VERTICES_MAX - 1);
+            indices[2] = (GLshort)index;
+
+            push_to_vertex_buffer_builder(&builder, indices, sizeof indices);
+        }
+    }
+
+    SDL_assert_always(buffer);
+
+    return buffer;
 }