OpenGL example now use the fixed function-pipeline. Code down by 120 lines.
diff --git a/examples/opengl_example/main.cpp b/examples/opengl_example/main.cpp
index cb5b8c4..44d77f5 100644
--- a/examples/opengl_example/main.cpp
+++ b/examples/opengl_example/main.cpp
@@ -2,87 +2,63 @@
#include <GL/glew.h>
#include <GLFW/glfw3.h>
#define STB_IMAGE_IMPLEMENTATION
-#include "stb_image.h" // for .png loading
+#include "stb_image.h" // for .png loading
#include "../../imgui.h"
#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
static GLFWwindow* window;
-static GLuint vbo;
-static GLuint vao;
-static GLuint vertexShader;
-static GLuint fragmentShader;
-static GLuint shaderProgram;
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)
+// 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)
{
- size_t total_vtx_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)
+ if (cmd_lists_count == 0)
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
glEnable(GL_BLEND);
glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
glDisable(GL_CULL_FACE);
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);
- glUseProgram(shaderProgram);
- const GLint uniMVP = glGetUniformLocation(shaderProgram, "MVP");
- const GLint uniClipRect = glGetUniformLocation(shaderProgram, "ClipRect");
+ glEnable(GL_TEXTURE_2D);
- // Setup orthographic projection matrix
- const float width = ImGui::GetIO().DisplaySize.x;
- const float height = ImGui::GetIO().DisplaySize.y;
- const float mvp[4][4] =
- {
- { 2.0f/width, 0.0f, 0.0f, 0.0f },
- { 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]);
+ // Setup matrices
+ glMatrixMode(GL_PROJECTION);
+ glLoadIdentity();
+ glOrtho(0.0f, ImGui::GetIO().DisplaySize.x, ImGui::GetIO().DisplaySize.y, 0.0f, -1.0f, +1.0f);
+ glMatrixMode(GL_MODELVIEW);
+ glLoadIdentity();
// Render command lists
- int vtx_offset = 0;
for (int n = 0; n < cmd_lists_count; 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();
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);
vtx_offset += pcmd->vtx_count;
}
}
-
- // Cleanup GL state
- glBindTexture(GL_TEXTURE_2D, 0);
- glBindVertexArray(0);
- glBindBuffer(GL_ARRAY_BUFFER, 0);
- glUseProgram(0);
+ glDisable(GL_SCISSOR_TEST);
}
static const char* ImImpl_GetClipboardTextFn()
@@ -103,42 +79,10 @@
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
static void glfw_error_callback(int error, const char* description)
{
- fputs(description, stderr);
+ fputs(description, stderr);
}
static float mouse_wheel = 0.0f;
@@ -169,29 +113,17 @@
{
glfwSetErrorCallback(glfw_error_callback);
- if (!glfwInit())
- exit(1);
+ if (!glfwInit())
+ 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);
window = glfwCreateWindow(1280, 720, "ImGui OpenGL example", NULL, NULL);
glfwMakeContextCurrent(window);
-
glfwSetKeyCallback(window, glfw_key_callback);
glfwSetScrollCallback(window, glfw_scroll_callback);
glfwSetCharCallback(window, glfw_char_callback);
- glewExperimental = GL_TRUE;
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()
@@ -200,10 +132,10 @@
glfwGetWindowSize(window, &w, &h);
ImGuiIO& io = ImGui::GetIO();
- 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.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.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.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.
io.KeyMap[ImGuiKey_LeftArrow] = GLFW_KEY_LEFT;
io.KeyMap[ImGuiKey_RightArrow] = GLFW_KEY_RIGHT;
io.KeyMap[ImGuiKey_UpArrow] = GLFW_KEY_UP;
@@ -225,68 +157,11 @@
io.SetClipboardTextFn = ImImpl_SetClipboardTextFn;
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
glGenTextures(1, &fontTex);
glBindTexture(GL_TEXTURE_2D, fontTex);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
-
const void* png_data;
unsigned int png_size;
ImGui::GetDefaultFontData(NULL, NULL, &png_data, &png_size);
@@ -299,13 +174,6 @@
void Shutdown()
{
ImGui::Shutdown();
-
- glDeleteProgram(shaderProgram);
- glDeleteShader(fragmentShader);
- glDeleteShader(vertexShader);
- glDeleteBuffers(1, &vbo);
- glDeleteVertexArrays(1, &vao);
-
glfwTerminate();
}
@@ -326,10 +194,10 @@
time = current_time;
double 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[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;
ImGui::NewFrame();
@@ -356,7 +224,7 @@
if (show_test_window)
{
// 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);
}
@@ -367,9 +235,10 @@
ImGui::End();
}
- // 3) Rendering
- glClearColor(0.8f, 0.6f, 0.6f, 1.0f);
- glClear(GL_COLOR_BUFFER_BIT);
+ // 3) Rendering
+ glViewport(0, 0, (int)io.DisplaySize.x, (int)io.DisplaySize.y);
+ glClearColor(0.8f, 0.6f, 0.6f, 1.0f);
+ glClear(GL_COLOR_BUFFER_BIT);
ImGui::Render();
glfwSwapBuffers(window);
