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OpenGL example now use the fixed function-pipeline. Code down by 120 lines.

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ocornut 2014-08-13 11:43:51 +01:00
parent ddc7f8b0b0
commit cb3d503941
1 changed files with 39 additions and 170 deletions
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209
examples/opengl_example/main.cpp
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@ -2,87 +2,63 @@
#include <GL/glew.h> #include <GL/glew.h>
#include <GLFW/glfw3.h> #include <GLFW/glfw3.h>
#define STB_IMAGE_IMPLEMENTATION #define STB_IMAGE_IMPLEMENTATION
#include "stb_image.h" // for .png loading #include "stb_image.h" // for .png loading
#include "../../imgui.h" #include "../../imgui.h"
#ifdef _MSC_VER #ifdef _MSC_VER
#pragma warning (disable: 4996) // 'This function or variable may be unsafe': strcpy, strdup, sprintf, vsnprintf, sscanf, fopen #pragma warning (disable: 4996) // 'This function or variable may be unsafe': strcpy, strdup, sprintf, vsnprintf, sscanf, fopen
#endif #endif
static GLFWwindow* window; static GLFWwindow* window;
static GLuint vbo;
static GLuint vao;
static GLuint vertexShader;
static GLuint fragmentShader;
static GLuint shaderProgram;
static GLuint fontTex; static GLuint fontTex;
// This is the main rendering function that you have to implement and provide to ImGui (via setting up 'RenderDrawListsFn' in the ImGuiIO structuer) // This is the main rendering function that you have to implement and provide to ImGui (via setting up 'RenderDrawListsFn' in the ImGuiIO structuer)
// We are using the fixed pipeline.
// A faster way would be to collate all vertices from all cmd_lists into a single vertex buffer
static void ImImpl_RenderDrawLists(ImDrawList** const cmd_lists, int cmd_lists_count) static void ImImpl_RenderDrawLists(ImDrawList** const cmd_lists, int cmd_lists_count)
{ {
size_t total_vtx_count = 0; if (cmd_lists_count == 0)
for (int n = 0; n < cmd_lists_count; n++)
total_vtx_count += cmd_lists[n]->vtx_buffer.size();
if (total_vtx_count == 0)
return; return;
// 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;
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);
}
glUnmapBuffer(GL_ARRAY_BUFFER);
// Setup render state: alpha-blending enabled, no face culling, no depth testing // Setup render state: alpha-blending enabled, no face culling, no depth testing
glEnable(GL_BLEND); glEnable(GL_BLEND);
glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA); glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
glDisable(GL_CULL_FACE); glDisable(GL_CULL_FACE);
glDisable(GL_DEPTH_TEST); glDisable(GL_DEPTH_TEST);
//glEnable(GL_SCISSOR_TEST);
glEnableClientState(GL_VERTEX_ARRAY);
glEnableClientState(GL_TEXTURE_COORD_ARRAY);
glEnableClientState(GL_COLOR_ARRAY);
// Bind texture and enable our shader // Bind texture
glBindTexture(GL_TEXTURE_2D, fontTex); glBindTexture(GL_TEXTURE_2D, fontTex);
glUseProgram(shaderProgram); glEnable(GL_TEXTURE_2D);
const GLint uniMVP = glGetUniformLocation(shaderProgram, "MVP");
const GLint uniClipRect = glGetUniformLocation(shaderProgram, "ClipRect");
// Setup orthographic projection matrix // Setup matrices
const float width = ImGui::GetIO().DisplaySize.x; glMatrixMode(GL_PROJECTION);
const float height = ImGui::GetIO().DisplaySize.y; glLoadIdentity();
const float mvp[4][4] = glOrtho(0.0f, ImGui::GetIO().DisplaySize.x, ImGui::GetIO().DisplaySize.y, 0.0f, -1.0f, +1.0f);
{ glMatrixMode(GL_MODELVIEW);
{ 2.0f/width, 0.0f, 0.0f, 0.0f }, glLoadIdentity();
{ 0.0f, 2.0f/-height, 0.0f, 0.0f },
{ 0.0f, 0.0f, -1.0f, 0.0f },
{ -1.0f, 1.0f, 0.0f, 1.0f },
};
glUniformMatrix4fv(uniMVP, 1, GL_FALSE, &mvp[0][0]);
// Render command lists // Render command lists
int vtx_offset = 0;
for (int n = 0; n < cmd_lists_count; n++) for (int n = 0; n < cmd_lists_count; n++)
{ {
const ImDrawList* cmd_list = cmd_lists[n]; const ImDrawList* cmd_list = cmd_lists[n];
const unsigned char* vtx_buffer = (const unsigned char*)cmd_list->vtx_buffer.begin();
glVertexPointer(2, GL_FLOAT, sizeof(ImDrawVert), (void*)(vtx_buffer));
glTexCoordPointer(2, GL_FLOAT, sizeof(ImDrawVert), (void*)(vtx_buffer+8));
glColorPointer(4, GL_UNSIGNED_BYTE, sizeof(ImDrawVert), (void*)(vtx_buffer+16));
int vtx_offset = 0;
const ImDrawCmd* pcmd_end = cmd_list->commands.end(); const ImDrawCmd* pcmd_end = cmd_list->commands.end();
for (const ImDrawCmd* pcmd = cmd_list->commands.begin(); pcmd != pcmd_end; pcmd++) for (const ImDrawCmd* pcmd = cmd_list->commands.begin(); pcmd != pcmd_end; pcmd++)
{ {
glUniform4fv(uniClipRect, 1, (float*)&pcmd->clip_rect); glScissor((int)pcmd->clip_rect.x, (int)pcmd->clip_rect.y, (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); glDrawArrays(GL_TRIANGLES, vtx_offset, pcmd->vtx_count);
vtx_offset += pcmd->vtx_count; vtx_offset += pcmd->vtx_count;
} }
} }
glDisable(GL_SCISSOR_TEST);
// Cleanup GL state
glBindTexture(GL_TEXTURE_2D, 0);
glBindVertexArray(0);
glBindBuffer(GL_ARRAY_BUFFER, 0);
glUseProgram(0);
} }
static const char* ImImpl_GetClipboardTextFn() static const char* ImImpl_GetClipboardTextFn()
@ -103,42 +79,10 @@ static void ImImpl_SetClipboardTextFn(const char* text, const char* text_end)
free(buf); free(buf);
} }
// Shader sources
const GLchar* vertexSource =
"#version 150 core\n"
"uniform mat4 MVP;"
"in vec2 i_pos;"
"in vec2 i_uv;"
"in vec4 i_col;"
"out vec4 col;"
"out vec2 pixel_pos;"
"out vec2 uv;"
"void main() {"
" col = i_col;"
" pixel_pos = i_pos;"
" uv = i_uv;"
" gl_Position = MVP * vec4(i_pos.x, i_pos.y, 0.0f, 1.0f);"
"}";
const GLchar* fragmentSource =
"#version 150 core\n"
"uniform sampler2D Tex;"
"uniform vec4 ClipRect;"
"in vec4 col;"
"in vec2 pixel_pos;"
"in vec2 uv;"
"out vec4 o_col;"
"void main() {"
" o_col = texture(Tex, uv) * col;"
//" if (pixel_pos.x < ClipRect.x || pixel_pos.y < ClipRect.y || pixel_pos.x > ClipRect.z || pixel_pos.y > ClipRect.w) discard;" // Clipping: using discard
//" if (step(ClipRect.x,pixel_pos.x) * step(ClipRect.y,pixel_pos.y) * step(pixel_pos.x,ClipRect.z) * step(pixel_pos.y,ClipRect.w) < 1.0f) discard;" // Clipping: using discard and step
" 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 // GLFW callbacks to get events
static void glfw_error_callback(int error, const char* description) static void glfw_error_callback(int error, const char* description)
{ {
fputs(description, stderr); fputs(description, stderr);
} }
static float mouse_wheel = 0.0f; static float mouse_wheel = 0.0f;
@ -169,29 +113,17 @@ void InitGL()
{ {
glfwSetErrorCallback(glfw_error_callback); glfwSetErrorCallback(glfw_error_callback);
if (!glfwInit()) if (!glfwInit())
exit(1); exit(1);
glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3);
glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 2);
glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);
glfwWindowHint(GLFW_OPENGL_FORWARD_COMPAT, GL_TRUE);
glfwWindowHint(GLFW_REFRESH_RATE, 60);
glfwWindowHint(GLFW_RESIZABLE, GL_FALSE); glfwWindowHint(GLFW_RESIZABLE, GL_FALSE);
window = glfwCreateWindow(1280, 720, "ImGui OpenGL example", NULL, NULL); window = glfwCreateWindow(1280, 720, "ImGui OpenGL example", NULL, NULL);
glfwMakeContextCurrent(window); glfwMakeContextCurrent(window);
glfwSetKeyCallback(window, glfw_key_callback); glfwSetKeyCallback(window, glfw_key_callback);
glfwSetScrollCallback(window, glfw_scroll_callback); glfwSetScrollCallback(window, glfw_scroll_callback);
glfwSetCharCallback(window, glfw_char_callback); glfwSetCharCallback(window, glfw_char_callback);
glewExperimental = GL_TRUE;
glewInit(); glewInit();
// After calling glewInit() our GL error state may be GL_INVALID_ENUM
const GLenum err = glGetError();
(void)err;
IM_ASSERT(err == GL_NO_ERROR || err == GL_INVALID_ENUM);
} }
void InitImGui() void InitImGui()
@ -200,10 +132,10 @@ void InitImGui()
glfwGetWindowSize(window, &w, &h); glfwGetWindowSize(window, &w, &h);
ImGuiIO& io = ImGui::GetIO(); ImGuiIO& io = ImGui::GetIO();
io.DisplaySize = ImVec2((float)w, (float)h); // Display size, in pixels. For clamping windows positions. io.DisplaySize = ImVec2((float)w, (float)h); // Display size, in pixels. For clamping windows positions.
io.DeltaTime = 1.0f/60.0f; // Time elapsed since last frame, in seconds (in this sample app we'll override this every frame because our timestep is variable) io.DeltaTime = 1.0f/60.0f; // Time elapsed since last frame, in seconds (in this sample app we'll override this every frame because our timestep is variable)
io.PixelCenterOffset = 0.5f; // Align OpenGL texels io.PixelCenterOffset = 0.5f; // Align OpenGL texels
io.KeyMap[ImGuiKey_Tab] = GLFW_KEY_TAB; // Keyboard mapping. ImGui will use those indices to peek into the io.KeyDown[] array that we will update during the application lifetime. io.KeyMap[ImGuiKey_Tab] = GLFW_KEY_TAB; // Keyboard mapping. ImGui will use those indices to peek into the io.KeyDown[] array.
io.KeyMap[ImGuiKey_LeftArrow] = GLFW_KEY_LEFT; io.KeyMap[ImGuiKey_LeftArrow] = GLFW_KEY_LEFT;
io.KeyMap[ImGuiKey_RightArrow] = GLFW_KEY_RIGHT; io.KeyMap[ImGuiKey_RightArrow] = GLFW_KEY_RIGHT;
io.KeyMap[ImGuiKey_UpArrow] = GLFW_KEY_UP; io.KeyMap[ImGuiKey_UpArrow] = GLFW_KEY_UP;
@ -225,68 +157,11 @@ void InitImGui()
io.SetClipboardTextFn = ImImpl_SetClipboardTextFn; io.SetClipboardTextFn = ImImpl_SetClipboardTextFn;
io.GetClipboardTextFn = ImImpl_GetClipboardTextFn; io.GetClipboardTextFn = ImImpl_GetClipboardTextFn;
// Setup graphics backend
GLint status = GL_TRUE;
GLenum err = GL_NO_ERROR;
err = glGetError(); IM_ASSERT(err == GL_NO_ERROR);
// Create and compile the vertex shader
vertexShader = glCreateShader(GL_VERTEX_SHADER);
glShaderSource(vertexShader, 1, &vertexSource, NULL);
glCompileShader(vertexShader);
glGetShaderiv(vertexShader, GL_COMPILE_STATUS, &status);
if (status != GL_TRUE)
{
char buffer[512];
glGetShaderInfoLog(vertexShader, 1024, NULL, buffer);
printf("%s", buffer);
IM_ASSERT(status == GL_TRUE);
}
// Create and compile the fragment shader
fragmentShader = glCreateShader(GL_FRAGMENT_SHADER);
glShaderSource(fragmentShader, 1, &fragmentSource, NULL);
glCompileShader(fragmentShader);
glGetShaderiv(vertexShader, GL_COMPILE_STATUS, &status);
IM_ASSERT(status == GL_TRUE);
// Link the vertex and fragment shader into a shader program
shaderProgram = glCreateProgram();
glAttachShader(shaderProgram, vertexShader);
glAttachShader(shaderProgram, fragmentShader);
glBindFragDataLocation(shaderProgram, 0, "o_col");
glLinkProgram(shaderProgram);
glGetProgramiv(shaderProgram, GL_LINK_STATUS, &status);
IM_ASSERT(status == GL_TRUE);
// Create Vertex Buffer Objects & Vertex Array Objects
glGenBuffers(1, &vbo);
glBindBuffer(GL_ARRAY_BUFFER, vbo);
glGenVertexArrays(1, &vao);
glBindVertexArray(vao);
GLint posAttrib = glGetAttribLocation(shaderProgram, "i_pos");
glVertexAttribPointer(posAttrib, 2, GL_FLOAT, GL_FALSE, sizeof(ImDrawVert), 0);
glEnableVertexAttribArray(posAttrib);
GLint uvAttrib = glGetAttribLocation(shaderProgram, "i_uv");
glEnableVertexAttribArray(uvAttrib);
glVertexAttribPointer(uvAttrib, 2, GL_FLOAT, GL_FALSE, sizeof(ImDrawVert), (void*)(2*sizeof(float)));
GLint colAttrib = glGetAttribLocation(shaderProgram, "i_col");
glVertexAttribPointer(colAttrib, 4, GL_UNSIGNED_BYTE, GL_TRUE, sizeof(ImDrawVert), (void*)(4*sizeof(float)));
glEnableVertexAttribArray(colAttrib);
err = glGetError(); IM_ASSERT(err == GL_NO_ERROR);
glBindVertexArray(0);
glBindBuffer(GL_ARRAY_BUFFER, 0);
// Load font texture // Load font texture
glGenTextures(1, &fontTex); glGenTextures(1, &fontTex);
glBindTexture(GL_TEXTURE_2D, fontTex); glBindTexture(GL_TEXTURE_2D, fontTex);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
const void* png_data; const void* png_data;
unsigned int png_size; unsigned int png_size;
ImGui::GetDefaultFontData(NULL, NULL, &png_data, &png_size); ImGui::GetDefaultFontData(NULL, NULL, &png_data, &png_size);
@ -299,13 +174,6 @@ void InitImGui()
void Shutdown() void Shutdown()
{ {
ImGui::Shutdown(); ImGui::Shutdown();
glDeleteProgram(shaderProgram);
glDeleteShader(fragmentShader);
glDeleteShader(vertexShader);
glDeleteBuffers(1, &vbo);
glDeleteVertexArrays(1, &vao);
glfwTerminate(); glfwTerminate();
} }
@ -326,10 +194,10 @@ int main(int argc, char** argv)
time = current_time; time = current_time;
double mouse_x, mouse_y; double mouse_x, mouse_y;
glfwGetCursorPos(window, &mouse_x, &mouse_y); glfwGetCursorPos(window, &mouse_x, &mouse_y);
io.MousePos = ImVec2((float)mouse_x, (float)mouse_y); // Mouse position, in pixels (set to -1,-1 if no mouse / on another screen, etc.) io.MousePos = ImVec2((float)mouse_x, (float)mouse_y); // Mouse position, in pixels (set to -1,-1 if no mouse / on another screen, etc.)
io.MouseDown[0] = glfwGetMouseButton(window, GLFW_MOUSE_BUTTON_LEFT) != 0; io.MouseDown[0] = glfwGetMouseButton(window, GLFW_MOUSE_BUTTON_LEFT) != 0;
io.MouseDown[1] = glfwGetMouseButton(window, GLFW_MOUSE_BUTTON_RIGHT) != 0; io.MouseDown[1] = glfwGetMouseButton(window, GLFW_MOUSE_BUTTON_RIGHT) != 0;
io.MouseWheel = (mouse_wheel != 0) ? mouse_wheel > 0.0f ? 1 : - 1 : 0; // Mouse wheel: -1,0,+1 io.MouseWheel = (mouse_wheel != 0) ? mouse_wheel > 0.0f ? 1 : - 1 : 0; // Mouse wheel: -1,0,+1
mouse_wheel = 0.0f; mouse_wheel = 0.0f;
ImGui::NewFrame(); ImGui::NewFrame();
@ -356,7 +224,7 @@ int main(int argc, char** argv)
if (show_test_window) if (show_test_window)
{ {
// More example code in ShowTestWindow() // More example code in ShowTestWindow()
ImGui::SetNewWindowDefaultPos(ImVec2(650, 20)); // Normally user code doesn't need/want to call it because positions are saved in .ini file anyway. Here we just want to make the demo initial state a bit more friendly! ImGui::SetNewWindowDefaultPos(ImVec2(650, 20)); // Normally user code doesn't need/want to call it because positions are saved in .ini file anyway. Here we just want to make the demo initial state a bit more friendly!
ImGui::ShowTestWindow(&show_test_window); ImGui::ShowTestWindow(&show_test_window);
} }
@ -367,9 +235,10 @@ int main(int argc, char** argv)
ImGui::End(); ImGui::End();
} }
// 3) Rendering // 3) Rendering
glClearColor(0.8f, 0.6f, 0.6f, 1.0f); glViewport(0, 0, (int)io.DisplaySize.x, (int)io.DisplaySize.y);
glClear(GL_COLOR_BUFFER_BIT); glClearColor(0.8f, 0.6f, 0.6f, 1.0f);
glClear(GL_COLOR_BUFFER_BIT);
ImGui::Render(); ImGui::Render();
glfwSwapBuffers(window); glfwSwapBuffers(window);