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Tidying up example applications

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This commit is contained in:
ocornut
2014-08-11 16:17:59 +01:00
parent 86d2c9d232
commit 4020ef7b58
2 changed files with 62 additions and 73 deletions
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80
examples/opengl_example/main.cpp
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@ -18,6 +18,7 @@ static GLuint fontTex;
static GLint uniMVP;
static GLint uniClipRect;
// This is the main rendering function that you have to implement and provide to ImGui (via setting up 'RenderDrawListsFn' in the ImGuiIO structuer)
static void ImImpl_RenderDrawLists(ImDrawList** const cmd_lists, int cmd_lists_count)
{
size_t total_vtx_count = 0;
@ -26,12 +27,34 @@ static void ImImpl_RenderDrawLists(ImDrawList** const cmd_lists, int cmd_lists_c
if (total_vtx_count == 0)
return;
int read_pos_clip_rect_buf = 0; // offset in 'clip_rect_buffer'. each PushClipRect command consume 1 of those.
// Copy all vertices into a single contiguous GL buffer
glBindBuffer(GL_ARRAY_BUFFER, vbo);
glBindVertexArray(vao);
glBufferData(GL_ARRAY_BUFFER, total_vtx_count * sizeof(ImDrawVert), NULL, GL_STREAM_DRAW);
unsigned char* buffer_data = (unsigned char*)glMapBuffer(GL_ARRAY_BUFFER, GL_WRITE_ONLY);
if (!buffer_data)
return;
int vtx_consumed = 0;
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);
vtx_consumed += cmd_list->vtx_buffer.size();
}
glUnmapBuffer(GL_ARRAY_BUFFER);
// Setup render state: alpha-blending enabled, no face culling, no depth testing
glEnable(GL_BLEND);
glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
glDisable(GL_CULL_FACE);
glDisable(GL_DEPTH_TEST);
ImVector<ImVec4> clip_rect_stack;
clip_rect_stack.push_back(ImVec4(-9999,-9999,+9999,+9999));
// Bind texture and enable our shader
glBindTexture(GL_TEXTURE_2D, fontTex);
glUseProgram(shaderProgram);
// Setup orthographic projection
// Setup orthographic projection matrix
const float L = 0.0f;
const float R = ImGui::GetIO().DisplaySize.x;
const float B = ImGui::GetIO().DisplaySize.y;
@ -43,48 +66,23 @@ static void ImImpl_RenderDrawLists(ImDrawList** const cmd_lists, int cmd_lists_c
{ 0.0f, 0.0f, -1.0f, 0.0f },
{ -(R+L)/(R-L), -(T+B)/(T-B), 0.0f, 1.0f },
};
glBindBuffer(GL_ARRAY_BUFFER, vbo);
glBindVertexArray(vao);
glBufferData(GL_ARRAY_BUFFER, total_vtx_count * sizeof(ImDrawVert), NULL, GL_STREAM_DRAW);
unsigned char* buffer_data = (unsigned char*)glMapBuffer(GL_ARRAY_BUFFER, GL_WRITE_ONLY);
if (!buffer_data)
return;
int vtx_consumed = 0;
for (int n = 0; n < cmd_lists_count; n++)
{
const ImDrawList* cmd_list = cmd_lists[n];
if (!cmd_list->vtx_buffer.empty())
{
memcpy(buffer_data, &cmd_list->vtx_buffer[0], cmd_list->vtx_buffer.size() * sizeof(ImDrawVert));
buffer_data += cmd_list->vtx_buffer.size() * sizeof(ImDrawVert);
vtx_consumed += cmd_list->vtx_buffer.size();
}
}
glUnmapBuffer(GL_ARRAY_BUFFER);
glUseProgram(shaderProgram);
glUniformMatrix4fv(uniMVP, 1, GL_FALSE, &mvp[0][0]);
// Setup render state: alpha-blending enabled, no face culling, no depth testing
glEnable(GL_BLEND);
glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
glDisable(GL_CULL_FACE);
glDisable(GL_DEPTH_TEST);
glBindTexture(GL_TEXTURE_2D, fontTex);
// Render command lists
vtx_consumed = 0; // offset in vertex buffer. each command consume ImDrawCmd::vtx_count of those
bool clip_rect_dirty = true;
for (int n = 0; n < cmd_lists_count; n++)
{
const ImDrawList* cmd_list = cmd_lists[n];
if (cmd_list->commands.empty() || cmd_list->vtx_buffer.empty())
continue;
// Setup stack of clipping rectangles
bool clip_rect_dirty = true;
int clip_rect_buf_consumed = 0;
ImVector<ImVec4> clip_rect_stack;
clip_rect_stack.push_back(ImVec4(-9999,-9999,+9999,+9999));
// Render command list
const ImDrawCmd* pcmd = &cmd_list->commands.front();
const ImDrawCmd* pcmd_end = &cmd_list->commands.back();
int clip_rect_buf_consumed = 0; // offset in cmd_list->clip_rect_buffer. each PushClipRect command consume 1 of those.
while (pcmd <= pcmd_end)
{
const ImDrawCmd& cmd = *pcmd++;
@ -132,7 +130,6 @@ static void ImImpl_SetClipboardTextFn(const char* text, const char* text_end)
}
// Shader sources
// FIXME-OPT: clip at vertex level
const GLchar* vertexSource =
"#version 150 core\n"
"uniform mat4 MVP;"
@ -164,6 +161,7 @@ const GLchar* fragmentSource =
" o_col.w *= (step(ClipRect.x,pixel_pos.x) * step(ClipRect.y,pixel_pos.y) * step(pixel_pos.x,ClipRect.z) * step(pixel_pos.y,ClipRect.w));" // Clipping: branch-less, set alpha 0.0f
"}";
// GLFW callbacks to get events
static void glfw_error_callback(int error, const char* description)
{
fputs(description, stderr);
@ -251,7 +249,6 @@ void InitImGui()
io.SetClipboardTextFn = ImImpl_SetClipboardTextFn;
io.GetClipboardTextFn = ImImpl_GetClipboardTextFn;
// Setup graphics backend
GLint status = GL_TRUE;
GLenum err = GL_NO_ERROR;
@ -394,7 +391,7 @@ int main(int argc, char** argv)
ImGui::End();
}
// 3) Render
// 3) Rendering
glClearColor(0.8f, 0.6f, 0.6f, 1.0f);
glClear(GL_COLOR_BUFFER_BIT);
ImGui::Render();
@ -403,6 +400,5 @@ int main(int argc, char** argv)
}
Shutdown();
return 0;
}