Examples: OpenGL3: Create the VAO in the render function so the setup can more easily be used with multiple shared GL context. (#1217)

This commit is contained in:
omar
2018-02-23 12:37:49 +01:00
parent 6662fe7b18
commit d749d49903
2 changed files with 38 additions and 32 deletions

View File

@ -13,6 +13,7 @@
// CHANGELOG
// (minor and older changes stripped away, please see git history for details)
// 2018-02-23: OpenGL: Create the VAO in the render function so the setup can more easily be used with multiple shared GL context.
// 2018-02-20: Inputs: Added support for mouse cursors (ImGui::GetMouseCursor() value and WM_SETCURSOR message handling).
// 2018-02-20: Inputs: Renamed GLFW callbacks exposed in .h to not include GL3 in their name.
// 2018-02-16: Misc: Obsoleted the io.RenderDrawListsFn callback and exposed ImGui_ImplGlfwGL3_RenderDrawData() in the .h file so you can call it yourself.
@ -54,7 +55,7 @@ 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 unsigned int g_VboHandle = 0, g_VaoHandle = 0, g_ElementsHandle = 0;
static unsigned int g_VboHandle = 0, g_ElementsHandle = 0;
// OpenGL3 Render function.
// (this used to be set in io.RenderDrawListsFn and called by ImGui::Render(), but you can now call this directly from your main loop)
@ -113,9 +114,22 @@ void ImGui_ImplGlfwGL3_RenderDrawData(ImDrawData* draw_data)
glUseProgram(g_ShaderHandle);
glUniform1i(g_AttribLocationTex, 0);
glUniformMatrix4fv(g_AttribLocationProjMtx, 1, GL_FALSE, &ortho_projection[0][0]);
glBindVertexArray(g_VaoHandle);
glBindSampler(0, 0); // Rely on combined texture/sampler state.
// Recreate the VAO every time
// (This is to easily allow multiple GL contexts. VAO are not shared among GL contexts, and we don't track creation/deletion of windows so we don't have an obvious key to use to cache them.)
GLuint vao_handle = 0;
glGenVertexArrays(1, &vao_handle);
glBindVertexArray(vao_handle);
glBindBuffer(GL_ARRAY_BUFFER, g_VboHandle);
glEnableVertexAttribArray(g_AttribLocationPosition);
glEnableVertexAttribArray(g_AttribLocationUV);
glEnableVertexAttribArray(g_AttribLocationColor);
glVertexAttribPointer(g_AttribLocationPosition, 2, GL_FLOAT, GL_FALSE, sizeof(ImDrawVert), (GLvoid*)IM_OFFSETOF(ImDrawVert, pos));
glVertexAttribPointer(g_AttribLocationUV, 2, GL_FLOAT, GL_FALSE, sizeof(ImDrawVert), (GLvoid*)IM_OFFSETOF(ImDrawVert, uv));
glVertexAttribPointer(g_AttribLocationColor, 4, GL_UNSIGNED_BYTE, GL_TRUE, sizeof(ImDrawVert), (GLvoid*)IM_OFFSETOF(ImDrawVert, col));
// Draw
for (int n = 0; n < draw_data->CmdListsCount; n++)
{
const ImDrawList* cmd_list = draw_data->CmdLists[n];
@ -289,17 +303,6 @@ bool ImGui_ImplGlfwGL3_CreateDeviceObjects()
glGenBuffers(1, &g_VboHandle);
glGenBuffers(1, &g_ElementsHandle);
glGenVertexArrays(1, &g_VaoHandle);
glBindVertexArray(g_VaoHandle);
glBindBuffer(GL_ARRAY_BUFFER, g_VboHandle);
glEnableVertexAttribArray(g_AttribLocationPosition);
glEnableVertexAttribArray(g_AttribLocationUV);
glEnableVertexAttribArray(g_AttribLocationColor);
glVertexAttribPointer(g_AttribLocationPosition, 2, GL_FLOAT, GL_FALSE, sizeof(ImDrawVert), (GLvoid*)IM_OFFSETOF(ImDrawVert, pos));
glVertexAttribPointer(g_AttribLocationUV, 2, GL_FLOAT, GL_FALSE, sizeof(ImDrawVert), (GLvoid*)IM_OFFSETOF(ImDrawVert, uv));
glVertexAttribPointer(g_AttribLocationColor, 4, GL_UNSIGNED_BYTE, GL_TRUE, sizeof(ImDrawVert), (GLvoid*)IM_OFFSETOF(ImDrawVert, col));
ImGui_ImplGlfwGL3_CreateFontsTexture();
// Restore modified GL state
@ -312,10 +315,9 @@ bool ImGui_ImplGlfwGL3_CreateDeviceObjects()
void ImGui_ImplGlfwGL3_InvalidateDeviceObjects()
{
if (g_VaoHandle) glDeleteVertexArrays(1, &g_VaoHandle);
if (g_VboHandle) glDeleteBuffers(1, &g_VboHandle);
if (g_ElementsHandle) glDeleteBuffers(1, &g_ElementsHandle);
g_VaoHandle = g_VboHandle = g_ElementsHandle = 0;
g_VboHandle = g_ElementsHandle = 0;
if (g_ShaderHandle && g_VertHandle) glDetachShader(g_ShaderHandle, g_VertHandle);
if (g_VertHandle) glDeleteShader(g_VertHandle);