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Indexed rendering. Not in main branch because breaks rendering code too much. Will merge in trunk along with more major graphics changes lat

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This commit is contained in:
ocornut
2015-04-09 21:05:35 +01:00
parent 500a8a0e02
commit 1746b04065
6 changed files with 210 additions and 125 deletions
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31
examples/opengl3_example/imgui_impl_glfw_gl3.cpp
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@ -23,7 +23,7 @@ static GLuint g_FontTexture = 0;
static int g_ShaderHandle = 0, g_VertHandle = 0, g_FragHandle = 0;
static int g_AttribLocationTex = 0, g_AttribLocationProjMtx = 0;
static int g_AttribLocationPosition = 0, g_AttribLocationUV = 0, g_AttribLocationColor = 0;
static size_t g_VboMaxSize = 20000;
static size_t g_VboSize = 0;
static unsigned int g_VboHandle = 0, g_VaoHandle = 0;
// This is the main rendering function that you have to implement and provide to ImGui (via setting up 'RenderDrawListsFn' in the ImGuiIO structure)
@ -62,32 +62,33 @@ static void ImGui_ImplGlfwGL3_RenderDrawLists(ImDrawList** const cmd_lists, int
for (int n = 0; n < cmd_lists_count; n++)
total_vtx_count += cmd_lists[n]->vtx_buffer.size();
glBindBuffer(GL_ARRAY_BUFFER, g_VboHandle);
size_t neededBufferSize = total_vtx_count * sizeof(ImDrawVert);
if (neededBufferSize > g_VboMaxSize)
size_t needed_vtx_size = total_vtx_count * sizeof(ImDrawVert);
if (g_VboSize < needed_vtx_size)
{
g_VboMaxSize = neededBufferSize + 5000; // Grow buffer
glBufferData(GL_ARRAY_BUFFER, g_VboMaxSize, NULL, GL_STREAM_DRAW);
g_VboSize = needed_vtx_size + 8192; // Grow buffer
glBufferData(GL_ARRAY_BUFFER, g_VboSize, NULL, GL_STREAM_DRAW);
}
// Copy and convert all vertices into a single contiguous buffer
unsigned char* buffer_data = (unsigned char*)glMapBuffer(GL_ARRAY_BUFFER, GL_WRITE_ONLY);
if (!buffer_data)
unsigned char* vtx_data = (unsigned char*)glMapBuffer(GL_ARRAY_BUFFER, GL_WRITE_ONLY);
if (!vtx_data)
return;
for (int n = 0; n < cmd_lists_count; n++)
{
const ImDrawList* cmd_list = cmd_lists[n];
memcpy(buffer_data, &cmd_list->vtx_buffer[0], cmd_list->vtx_buffer.size() * sizeof(ImDrawVert));
buffer_data += cmd_list->vtx_buffer.size() * sizeof(ImDrawVert);
memcpy(vtx_data, &cmd_list->vtx_buffer[0], cmd_list->vtx_buffer.size() * sizeof(ImDrawVert));
vtx_data += cmd_list->vtx_buffer.size() * sizeof(ImDrawVert);
}
glUnmapBuffer(GL_ARRAY_BUFFER);
glBindBuffer(GL_ARRAY_BUFFER, 0);
glBindVertexArray(g_VaoHandle);
int cmd_offset = 0;
int vtx_offset = 0;
for (int n = 0; n < cmd_lists_count; n++)
{
const ImDrawList* cmd_list = cmd_lists[n];
int vtx_offset = cmd_offset;
const ImDrawIdx* idx_buffer = (const unsigned short*)&cmd_list->idx_buffer.front();
const ImDrawCmd* pcmd_end = cmd_list->commands.end();
for (const ImDrawCmd* pcmd = cmd_list->commands.begin(); pcmd != pcmd_end; pcmd++)
{
@ -99,11 +100,11 @@ static void ImGui_ImplGlfwGL3_RenderDrawLists(ImDrawList** const cmd_lists, int
{
glBindTexture(GL_TEXTURE_2D, (GLuint)(intptr_t)pcmd->texture_id);
glScissor((int)pcmd->clip_rect.x, (int)(height - pcmd->clip_rect.w), (int)(pcmd->clip_rect.z - pcmd->clip_rect.x), (int)(pcmd->clip_rect.w - pcmd->clip_rect.y));
glDrawArrays(GL_TRIANGLES, vtx_offset, pcmd->vtx_count);
glDrawElementsBaseVertex(GL_TRIANGLES, pcmd->idx_count, GL_UNSIGNED_SHORT, idx_buffer, vtx_offset);
}
vtx_offset += pcmd->vtx_count;
idx_buffer += pcmd->idx_count;
}
cmd_offset = vtx_offset;
vtx_offset += cmd_list->vtx_buffer.size();
}
// Restore modified state
@ -217,8 +218,6 @@ bool ImGui_ImplGlfwGL3_CreateDeviceObjects()
g_AttribLocationColor = glGetAttribLocation(g_ShaderHandle, "Color");
glGenBuffers(1, &g_VboHandle);
glBindBuffer(GL_ARRAY_BUFFER, g_VboHandle);
glBufferData(GL_ARRAY_BUFFER, g_VboMaxSize, NULL, GL_DYNAMIC_DRAW);
glGenVertexArrays(1, &g_VaoHandle);
glBindVertexArray(g_VaoHandle);