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About Catch_0x16

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  1. Catch_0x16

    OpenGL OpenGL Framebuffer always black

    Ok small update, looks like when I call 'glCheckNAMEDFramebufferStatus' I get the return code of 36053, or 'GL_FRAMEBUFFER_COMPLETE' Quick question -> Do I need to re-define/re-compile shaders for the new framebuffer?
  2. Catch_0x16

    OpenGL OpenGL Framebuffer always black

    Thanks, I've been doing some digging since my last post and I've found some interesting things. Looks like when I generate my framebuffer, I am assigned a value of '1'. Later on during my draw call when I call 'glCheckFramebufferStatus' it returns 0. Further reading suggests that it only returns 0 when an error occurs. I'm now checking for errors before and after the call to check the framebuffer status and it looks like the call is generating the 1280 error 'GL_INVALID_ENUM'. According to the documentation GL_INVALID_ENUM should only occur if: Which leads me to suggest that my framebuffer value of 1 is perhaps no longer valid... Can you think of any reason this might occur? I am plugging into drawcalls of a much larger game engine that is making OpenGL calls left right and centre. I wonder if ID '1' is being hardcoded/assumed as something else? (Unlikely).
  3. Catch_0x16

    OpenGL OpenGL Framebuffer always black

    Oh cool, I see. Presumably it's just not necessary anymore? I will have to look into this in more detail later. I'm checking the framebuffer status but it seems to be returning 0, which at face value does not concern me, however it seems that GL_FRAMEBUFFER_COMPLETE is 0x8CD5 so something is going wrong. I will keep trying to work out what is going wrong but any intuition you may have would be appreciated. I feel like feeling silly frequently is a right of passage as a programmer. The days where I feel like I know what I am doing always make me concerned!
  4. Catch_0x16

    OpenGL OpenGL Framebuffer always black

    Thanks for the reply Green Baron. Other than the attractive black box down in the lower left, I can't really take credit for the image I've not blit the framebuffers contents... think that would be the problem? (I feel a bit silly now). I'm pretty new to OpenGL, what code am I using that is legacy versus 3+? I'm keen to improve so thanks for highlighting it.
  5. Hello Folks, I'm writing a plugin for a simulator called 'X-Plane 11'. My plugin essentially calls on a DLL (Which I've written) that makes OpenGL calls to draw graphics onto the active draw target (it does no OpenGL initialization). I want this external DLL to represent the logic behind a computer screen, but not be directly coupled with the OpenGL context that it is being drawn to. In this current instance for example, I am drawing it to the screen in X-Plane, however, I may at some point want to draw it to the screen of a different game engine, or perhaps even just a windows program. The way I am trying to achieve this: Generate a frame buffer and texture Initialize texture and add it to the framebuffer On the drawcall... Bind to the frame buffer Call the dll's draw method Un-bind the frame buffer Bind to the host applications framebuffer Bind to the associated texture Draw a quad in the corner of the screen with appropriate texture coordinates Un-bind the texture I have the problem though that the output is always just a black square...(See attached image) The code goes a little like this (Only showing the relevant bits): #include <Windows.h> #include <string> #include "PluginHeader.h" #include <GL\glew.h> #include <gl\GL.h> #include <gl\GLU.h> #include "MFDSim.h" HINSTANCE g_MfdSimLibHandle = 0; XPLMWindowID g_MfdWindowID = 0; GLuint g_FrameBufferID = 0; GLuint g_fbTex = 0; GLuint g_rbo = 0; unsigned int g_MfdScreenWidth = 0; unsigned int g_MfdScreenHeight = 0; ///////////////////////////////////////////////////// // Standard plugin functions ------------------------ PLUGIN_API int XPluginStart( char* outName, char* outSig, char* outDesc) { strcpy(outName,"MFD Sim"); strcpy(outSig, "mfd"); strcpy(outDesc, "); int retVal = TRUE; glewInit(); HINSTANCE g_MfdSimLibHandle = LoadLibrary("./Resources/plugins/MFD_Sim_Plugin/win_x64/MFDSim.dll"); if (g_MfdSimLibHandle != nullptr) { try { MFD::mfdInit("./Resources/plugins/MFD_Sim_Plugin/config/layout.xml"); MFD::mfdGetWidthHeight(g_MfdScreenWidth, g_MfdScreenHeight); } catch (const std::exception& ex) { retVal = FALSE; } } else { retVal = FALSE; } return retVal; } PLUGIN_API void XPluginStop() { FreeLibrary(g_MfdSimLibHandle); } PLUGIN_API int XPluginEnable() { // We need to revert back to the appropriate frame buffer after we're done GLint currentReadFB = 0; GLint currentDrawFB = 0; glGetIntegerv(GL_READ_FRAMEBUFFER, &currentReadFB); glGetIntegerv(GL_DRAW_FRAMEBUFFER, &currentDrawFB); XPLMRegisterDrawCallback(OnDrawCall, xplm_Phase_LastCockpit, TRUE, nullptr); // Generate OPENGL stuff we need glGenFramebuffers(1, &g_FrameBufferID); glBindFramebuffer(GL_FRAMEBUFFER, g_FrameBufferID); glGenTextures(1, &g_fbTex); glBindTexture(GL_TEXTURE_2D, g_fbTex); glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, g_MfdScreenWidth, g_MfdScreenHeight, 0, GL_RGB, GL_UNSIGNED_BYTE, nullptr); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR); glBindTexture(GL_TEXTURE_2D, 0); glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, g_fbTex, 0); glGenRenderbuffers(1, &g_rbo); glBindRenderbuffer(GL_RENDERBUFFER, g_rbo); glRenderbufferStorage(GL_RENDERBUFFER, GL_DEPTH24_STENCIL8, g_MfdScreenWidth, g_MfdScreenHeight); glBindRenderbuffer(GL_RENDERBUFFER, 0); glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_DEPTH_STENCIL_ATTACHMENT, GL_RENDERBUFFER, g_rbo); glBindFramebuffer(GL_READ_FRAMEBUFFER, currentReadFB); glBindFramebuffer(GL_DRAW_FRAMEBUFFER, currentDrawFB); return TRUE; } PLUGIN_API void XPluginDisable() { XPLMUnregisterDrawCallback(OnDrawCall, xplm_Phase_LastCockpit, TRUE, nullptr); glDeleteFramebuffers(1, &g_FrameBufferID); glDeleteTextures(1, &g_fbTex); } PLUGIN_API void XPluginReceiveMessage( XPLMPluginID inFrom, int inMsg, void* inParam) { } // Boilerplate DLL stuff BOOL WINAPI DLLMain( _In_ HINSTANCE hInstance, _In_ DWORD fdwReason, _In_ LPVOID lpvReserved) { return TRUE; } ///////////////////////////////////////////////////// // MFD functions ----------------------------------- void HandleWindowKeyEvent(XPLMWindowID inWindowID, char inKey, XPLMKeyFlags inFlags, char inVirtualKey, void * inRefcon, int losingFocus) { if (inWindowID == g_MfdWindowID) { } } int OnDrawCall(XPLMDrawingPhase inPhase, int inIsBefore, void * refCon) { // We need to revert back to the appropriate frame buffer after we're done GLint currentReadFB = 0; GLint currentDrawFB = 0; glGetIntegerv(GL_READ_FRAMEBUFFER, &currentReadFB); glGetIntegerv(GL_DRAW_FRAMEBUFFER, &currentDrawFB); // Bind to our own frame buffer and draw our MFD glBindFramebuffer(GL_DRAW_FRAMEBUFFER, g_FrameBufferID); glBindFramebuffer(GL_READ_FRAMEBUFFER, g_FrameBufferID); glBindTexture(GL_TEXTURE_2D, g_fbTex); glClear(GL_COLOR_BUFFER_BIT); glClearColor(0.0f, 0.0f, 0.0f, 1.0f); glEnable(GL_TEXTURE_2D); if (!MFD::mfdDraw(1.0f)) { // TODO: Handle failure to draw } glBegin(GL_LINES); glColor4f(1.0f, 0.1f, 0.1f, 1.0f); glVertex2f(0.0f, 0.0f); glVertex2f(100.0f, 100.0f); glEnd(); glBindFramebuffer(GL_READ_FRAMEBUFFER, currentReadFB); glBindFramebuffer(GL_DRAW_FRAMEBUFFER, currentDrawFB); glEnable(GL_TEXTURE_2D); glBegin(GL_QUADS); glVertex2f(0, 0); glTexCoord2f(0.0f, 0.0f); glVertex2f(0, g_MfdScreenHeight); glTexCoord2f(0.0f, 1.0f); glVertex2f(g_MfdScreenWidth, g_MfdScreenHeight); glTexCoord2f(1.0f, 1.0f); glVertex2f(g_MfdScreenWidth, 0); glTexCoord2f(1.0f, 0.0f); glEnd(); glBindTexture(GL_TEXTURE_2D, 0); return 0; }
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