I am an idiot: the quadtree code is now fixed.
authorDavid Gow <david@ingeniumdigital.com>
Wed, 13 Aug 2014 08:05:38 +0000 (16:05 +0800)
committerDavid Gow <david@ingeniumdigital.com>
Wed, 13 Aug 2014 08:10:02 +0000 (16:10 +0800)
tl;dr: needed more * by 2.

iab;wtd*: The index buffers on the GPU contain _two_ elements per object,
one for the top left of the object's bounding box, one for the bottom-right.
We were taking that into account when computing the number of indices to give
the DrawElements() call, but not when calculating the offset into the buffer.

Oops.

*: I am bored; want tedious detail

src/objectrenderer.cpp

index 998b62f..76aba52 100644 (file)
@@ -42,7 +42,7 @@ void ObjectRenderer::RenderUsingGPU(unsigned first_obj_id, unsigned last_obj_id)
 
        m_shader_program.Use();
        m_ibo.Bind();
-       glDrawElements(GL_LINES, (last_index-first_index)*2, GL_UNSIGNED_INT, (GLvoid*)(first_index*sizeof(uint32_t)));
+       glDrawElements(GL_LINES, (last_index-first_index)*2, GL_UNSIGNED_INT, (GLvoid*)(2*first_index*sizeof(uint32_t)));
 }
 
 
@@ -328,7 +328,7 @@ void BezierRenderer::RenderUsingGPU(unsigned first_obj_id, unsigned last_obj_id)
        glUniform1i(m_shader_program.GetUniformLocation("bezier_buffer_texture"), 0);
        glUniform1i(m_shader_program.GetUniformLocation("bezier_id_buffer_texture"), 1);
        m_ibo.Bind();
-       glDrawElements(GL_LINES, (last_index-first_index)*2, GL_UNSIGNED_INT, (GLvoid*)(first_index*sizeof(uint32_t)));
+       glDrawElements(GL_LINES, (last_index-first_index)*2, GL_UNSIGNED_INT, (GLvoid*)(2*first_index*sizeof(uint32_t)));
 }
 
 /**

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