• Advertisement
  • Popular Tags

  • Popular Now

  • Advertisement
  • Similar Content

    • By tj8146
      I am using immediate mode for OpenGL and I am creating a 2D top down car game. I am trying to configure my game loop in order to get my car-like physics working on a square shape. I have working code but it is not doing as I want it to. I am not sure as to whether it is my game loop that is incorrect or my code for the square is incorrect, or maybe both! Could someone help because I have been trying to work this out for over a day now
      I have attached my .cpp file if you wish to run it for yourself.. 
      WinMain code:
      /******************* WIN32 FUNCTIONS ***************************/ int WINAPI WinMain( HINSTANCE hInstance, // Instance HINSTANCE hPrevInstance, // Previous Instance LPSTR lpCmdLine, // Command Line Parameters int nCmdShow) // Window Show State { MSG msg; // Windows Message Structure bool done=false; // Bool Variable To Exit Loop Car car; car.x = 220; car.y = 140; car.dx = 0; car.dy = 0; car.ang = 0; AllocConsole(); FILE *stream; freopen_s(&stream, "CONOUT$", "w", stdout); // Create Our OpenGL Window if (!CreateGLWindow("OpenGL Win32 Example",screenWidth,screenHeight)) { return 0; // Quit If Window Was Not Created } while(!done) // Loop That Runs While done=FALSE { if (PeekMessage(&msg,NULL,0,0,PM_REMOVE)) // Is There A Message Waiting? { if (msg.message==WM_QUIT) // Have We Received A Quit Message? { done=true; // If So done=TRUE break; } else // If Not, Deal With Window Messages { TranslateMessage(&msg); // Translate The Message DispatchMessage(&msg); // Dispatch The Message } } else // If There Are No Messages { if(keys[VK_ESCAPE]) done = true; void processKeys(Car& car); //process keyboard while (game_is_running) { loops = 0; while (GetTickCount() > next_game_tick && loops < MAX_FRAMESKIP) { update(car); // update variables next_game_tick += SKIP_TICKS; loops++; } display(car); // Draw The Scene SwapBuffers(hDC); // Swap Buffers (Double Buffering) } } } // Shutdown KillGLWindow(); // Kill The Window return (int)(msg.wParam); // Exit The Program } //WIN32 Processes function - useful for responding to user inputs or other events. LRESULT CALLBACK WndProc( HWND hWnd, // Handle For This Window UINT uMsg, // Message For This Window WPARAM wParam, // Additional Message Information LPARAM lParam) // Additional Message Information { switch (uMsg) // Check For Windows Messages { case WM_CLOSE: // Did We Receive A Close Message? { PostQuitMessage(0); // Send A Quit Message return 0; // Jump Back } break; case WM_SIZE: // Resize The OpenGL Window { reshape(LOWORD(lParam),HIWORD(lParam)); // LoWord=Width, HiWord=Height return 0; // Jump Back } break; case WM_LBUTTONDOWN: { mouse_x = LOWORD(lParam); mouse_y = screenHeight - HIWORD(lParam); LeftPressed = true; } break; case WM_LBUTTONUP: { LeftPressed = false; } break; case WM_MOUSEMOVE: { mouse_x = LOWORD(lParam); mouse_y = screenHeight - HIWORD(lParam); } break; case WM_KEYDOWN: // Is A Key Being Held Down? { keys[wParam] = true; // If So, Mark It As TRUE return 0; // Jump Back } break; case WM_KEYUP: // Has A Key Been Released? { keys[wParam] = false; // If So, Mark It As FALSE return 0; // Jump Back } break; } // Pass All Unhandled Messages To DefWindowProc return DefWindowProc(hWnd,uMsg,wParam,lParam); }  
      C++ and OpenGL code:
      int mouse_x=0, mouse_y=0; bool LeftPressed = false; int screenWidth=1080, screenHeight=960; bool keys[256]; float radiansFromDegrees(float deg) { return deg * (M_PI / 180.0f); } float degreesFromRadians(float rad) { return rad / (M_PI / 180.0f); } bool game_is_running = true; const int TICKS_PER_SECOND = 50; const int SKIP_TICKS = 1000 / TICKS_PER_SECOND; const int MAX_FRAMESKIP = 10; DWORD next_game_tick = GetTickCount(); int loops; typedef struct { float x, y; float dx, dy; float ang; }Car; //OPENGL FUNCTION PROTOTYPES void display(const Car& car); //called in winmain to draw everything to the screen void reshape(int width, int height); //called when the window is resized void init(); //called in winmain when the program starts. void processKeys(Car& car); //called in winmain to process keyboard input void update(Car& car); //called in winmain to update variables /************* START OF OPENGL FUNCTIONS ****************/ void display(const Car& car) { const float w = 50.0f; const float h = 50.0f; glClear(GL_COLOR_BUFFER_BIT); glLoadIdentity(); glTranslatef(100, 100, 0); glBegin(GL_POLYGON); glVertex2f(car.x, car.y); glVertex2f(car.x + w, car.y); glVertex2f(car.x + w, car.y + h); glVertex2f(car.x, car.y + h); glEnd(); glFlush(); } void reshape(int width, int height) // Resize the OpenGL window { screenWidth = width; screenHeight = height; // to ensure the mouse coordinates match // we will use these values to set the coordinate system glViewport(0, 0, width, height); // Reset the current viewport glMatrixMode(GL_PROJECTION); // select the projection matrix stack glLoadIdentity(); // reset the top of the projection matrix to an identity matrix gluOrtho2D(0, screenWidth, 0, screenHeight); // set the coordinate system for the window glMatrixMode(GL_MODELVIEW); // Select the modelview matrix stack glLoadIdentity(); // Reset the top of the modelview matrix to an identity matrix } void init() { glClearColor(1.0, 1.0, 0.0, 0.0); //sets the clear colour to yellow //glClear(GL_COLOR_BUFFER_BIT) in the display function //will clear the buffer to this colour. } void processKeys(Car& car) { if (keys[VK_UP]) { float cdx = sinf(radiansFromDegrees(car.ang)); float cdy = -cosf(radiansFromDegrees(car.ang)); car.dx += cdx; car.dy += cdy; } if (keys[VK_DOWN]) { float cdx = sinf(radiansFromDegrees(car.ang)); float cdy = -cosf(radiansFromDegrees(car.ang)); car.dx += -cdx; car.dy += -cdy; } if (keys[VK_LEFT]) { car.ang -= 2; } if (keys[VK_RIGHT]) { car.ang += 2; } } void update(Car& car) { car.x += car.dx*next_game_tick; }  
      game.cpp
    • By tj8146
      I am using immediate mode for OpenGL and I am creating a 2D top down car game. I am trying to configure my game loop in order to get my car-like physics working on a square shape. I have working code but it is not doing as I want it to. I am not sure as to whether it is my game loop that is incorrect or my code for the square is incorrect, or maybe both! Could someone help because I have been trying to work this out for over a day now
      I have attached my .cpp file if you wish to run it for yourself.. 
       
      This is my C++ and OpenGL code:
      int mouse_x=0, mouse_y=0; bool LeftPressed = false; int screenWidth=1080, screenHeight=960; bool keys[256]; float radiansFromDegrees(float deg) { return deg * (M_PI / 180.0f); } float degreesFromRadians(float rad) { return rad / (M_PI / 180.0f); } bool game_is_running = true; const int TICKS_PER_SECOND = 50; const int SKIP_TICKS = 1000 / TICKS_PER_SECOND; const int MAX_FRAMESKIP = 10; DWORD next_game_tick = GetTickCount(); int loops; typedef struct { float x, y; float dx, dy; float ang; }Car; //OPENGL FUNCTION PROTOTYPES void display(const Car& car); //called in winmain to draw everything to the screen void reshape(int width, int height); //called when the window is resized void init(); //called in winmain when the program starts. void processKeys(Car& car); //called in winmain to process keyboard input void update(Car& car); //called in winmain to update variables /************* START OF OPENGL FUNCTIONS ****************/ void display(const Car& car) { const float w = 50.0f; const float h = 50.0f; glClear(GL_COLOR_BUFFER_BIT); glLoadIdentity(); glTranslatef(100, 100, 0); glBegin(GL_POLYGON); glVertex2f(car.x, car.y); glVertex2f(car.x + w, car.y); glVertex2f(car.x + w, car.y + h); glVertex2f(car.x, car.y + h); glEnd(); glFlush(); } void reshape(int width, int height) // Resize the OpenGL window { screenWidth = width; screenHeight = height; // to ensure the mouse coordinates match // we will use these values to set the coordinate system glViewport(0, 0, width, height); // Reset the current viewport glMatrixMode(GL_PROJECTION); // select the projection matrix stack glLoadIdentity(); // reset the top of the projection matrix to an identity matrix gluOrtho2D(0, screenWidth, 0, screenHeight); // set the coordinate system for the window glMatrixMode(GL_MODELVIEW); // Select the modelview matrix stack glLoadIdentity(); // Reset the top of the modelview matrix to an identity matrix } void init() { glClearColor(1.0, 1.0, 0.0, 0.0); //sets the clear colour to yellow //glClear(GL_COLOR_BUFFER_BIT) in the display function //will clear the buffer to this colour. } void processKeys(Car& car) { if (keys[VK_UP]) { float cdx = sinf(radiansFromDegrees(car.ang)); float cdy = -cosf(radiansFromDegrees(car.ang)); car.dx += cdx; car.dy += cdy; } if (keys[VK_DOWN]) { float cdx = sinf(radiansFromDegrees(car.ang)); float cdy = -cosf(radiansFromDegrees(car.ang)); car.dx += -cdx; car.dy += -cdy; } if (keys[VK_LEFT]) { car.ang -= 2; } if (keys[VK_RIGHT]) { car.ang += 2; } } void update(Car& car) { car.x += car.dx*next_game_tick; } My WinMain code:
      /******************* WIN32 FUNCTIONS ***************************/ int WINAPI WinMain( HINSTANCE hInstance, // Instance HINSTANCE hPrevInstance, // Previous Instance LPSTR lpCmdLine, // Command Line Parameters int nCmdShow) // Window Show State { MSG msg; // Windows Message Structure bool done=false; // Bool Variable To Exit Loop Car car; car.x = 220; car.y = 140; car.dx = 0; car.dy = 0; car.ang = 0; AllocConsole(); FILE *stream; freopen_s(&stream, "CONOUT$", "w", stdout); // Create Our OpenGL Window if (!CreateGLWindow("OpenGL Win32 Example",screenWidth,screenHeight)) { return 0; // Quit If Window Was Not Created } while(!done) // Loop That Runs While done=FALSE { if (PeekMessage(&msg,NULL,0,0,PM_REMOVE)) // Is There A Message Waiting? { if (msg.message==WM_QUIT) // Have We Received A Quit Message? { done=true; // If So done=TRUE break; } else // If Not, Deal With Window Messages { TranslateMessage(&msg); // Translate The Message DispatchMessage(&msg); // Dispatch The Message } } else // If There Are No Messages { if(keys[VK_ESCAPE]) done = true; void processKeys(Car& car); //process keyboard while (game_is_running) { loops = 0; while (GetTickCount() > next_game_tick && loops < MAX_FRAMESKIP) { update(car); // update variables next_game_tick += SKIP_TICKS; loops++; } display(car); // Draw The Scene SwapBuffers(hDC); // Swap Buffers (Double Buffering) } } } // Shutdown KillGLWindow(); // Kill The Window return (int)(msg.wParam); // Exit The Program } //WIN32 Processes function - useful for responding to user inputs or other events. LRESULT CALLBACK WndProc( HWND hWnd, // Handle For This Window UINT uMsg, // Message For This Window WPARAM wParam, // Additional Message Information LPARAM lParam) // Additional Message Information { switch (uMsg) // Check For Windows Messages { case WM_CLOSE: // Did We Receive A Close Message? { PostQuitMessage(0); // Send A Quit Message return 0; // Jump Back } break; case WM_SIZE: // Resize The OpenGL Window { reshape(LOWORD(lParam),HIWORD(lParam)); // LoWord=Width, HiWord=Height return 0; // Jump Back } break; case WM_LBUTTONDOWN: { mouse_x = LOWORD(lParam); mouse_y = screenHeight - HIWORD(lParam); LeftPressed = true; } break; case WM_LBUTTONUP: { LeftPressed = false; } break; case WM_MOUSEMOVE: { mouse_x = LOWORD(lParam); mouse_y = screenHeight - HIWORD(lParam); } break; case WM_KEYDOWN: // Is A Key Being Held Down? { keys[wParam] = true; // If So, Mark It As TRUE return 0; // Jump Back } break; case WM_KEYUP: // Has A Key Been Released? { keys[wParam] = false; // If So, Mark It As FALSE return 0; // Jump Back } break; } // Pass All Unhandled Messages To DefWindowProc return DefWindowProc(hWnd,uMsg,wParam,lParam); }  
      game.cpp
    • By lxjk
      Hi guys,
      There are many ways to do light culling in tile-based shading. I've been playing with this idea for a while, and just want to throw it out there.
      Because tile frustums are general small compared to light radius, I tried using cone test to reduce false positives introduced by commonly used sphere-frustum test.
      On top of that, I use distance to camera rather than depth for near/far test (aka. sliced by spheres).
      This method can be naturally extended to clustered light culling as well.
      The following image shows the general ideas

       
      Performance-wise I get around 15% improvement over sphere-frustum test. You can also see how a single light performs as the following: from left to right (1) standard rendering of a point light; then tiles passed the test of (2) sphere-frustum test; (3) cone test; (4) spherical-sliced cone test
       

       
      I put the details in my blog post (https://lxjk.github.io/2018/03/25/Improve-Tile-based-Light-Culling-with-Spherical-sliced-Cone.html), GLSL source code included!
       
      Eric
    • By Fadey Duh
      Good evening everyone!

      I was wondering if there is something equivalent of  GL_NV_blend_equation_advanced for AMD?
      Basically I'm trying to find more compatible version of it.

      Thank you!
    • By Jens Eckervogt
      Hello guys, 
       
      Please tell me! 
      How do I know? Why does wavefront not show for me?
      I already checked I have non errors yet.
      using OpenTK; using System.Collections.Generic; using System.IO; using System.Text; namespace Tutorial_08.net.sourceskyboxer { public class WaveFrontLoader { private static List<Vector3> inPositions; private static List<Vector2> inTexcoords; private static List<Vector3> inNormals; private static List<float> positions; private static List<float> texcoords; private static List<int> indices; public static RawModel LoadObjModel(string filename, Loader loader) { inPositions = new List<Vector3>(); inTexcoords = new List<Vector2>(); inNormals = new List<Vector3>(); positions = new List<float>(); texcoords = new List<float>(); indices = new List<int>(); int nextIdx = 0; using (var reader = new StreamReader(File.Open("Contents/" + filename + ".obj", FileMode.Open), Encoding.UTF8)) { string line = reader.ReadLine(); int i = reader.Read(); while (true) { string[] currentLine = line.Split(); if (currentLine[0] == "v") { Vector3 pos = new Vector3(float.Parse(currentLine[1]), float.Parse(currentLine[2]), float.Parse(currentLine[3])); inPositions.Add(pos); if (currentLine[1] == "t") { Vector2 tex = new Vector2(float.Parse(currentLine[1]), float.Parse(currentLine[2])); inTexcoords.Add(tex); } if (currentLine[1] == "n") { Vector3 nom = new Vector3(float.Parse(currentLine[1]), float.Parse(currentLine[2]), float.Parse(currentLine[3])); inNormals.Add(nom); } } if (currentLine[0] == "f") { Vector3 pos = inPositions[0]; positions.Add(pos.X); positions.Add(pos.Y); positions.Add(pos.Z); Vector2 tc = inTexcoords[0]; texcoords.Add(tc.X); texcoords.Add(tc.Y); indices.Add(nextIdx); ++nextIdx; } reader.Close(); return loader.loadToVAO(positions.ToArray(), texcoords.ToArray(), indices.ToArray()); } } } } } And It have tried other method but it can't show for me.  I am mad now. Because any OpenTK developers won't help me.
      Please help me how do I fix.

      And my download (mega.nz) should it is original but I tried no success...
      - Add blend source and png file here I have tried tried,.....  
       
      PS: Why is our community not active? I wait very longer. Stop to lie me!
      Thanks !
  • Advertisement
  • Advertisement
Sign in to follow this  

OpenGL Improve performance: Render 100000+ objects

This topic is 2231 days old which is more than the 365 day threshold we allow for new replies. Please post a new topic.

If you intended to correct an error in the post then please contact us.

Recommended Posts

Hello,

We prepared a little test project (VS 2010, C++, OpenGl, Freeglut, Glew) to publish our solution to the following main requirements:


- Rendering 100000+ objects at the same time, each one of those independently accessible/seleccionable to be able to change their properties.

- The objects are of a certain type that defines their general shape and properties, which is also changeable during execution.

- Use OF VBOs, Shaders, OpenGl 3.3

- Should work on low-level graphic cards.



This is a very simplified version of our actual project, we are aware of some general methods to improve overall performance such as rendering only the visible objects and not those which are temporarily outside of your frustum.

For this example we took those techniques and other features out to make it smaller and easier to understand.

But please don't hold back with anything that comes to your mind and works for you, we might as well have missed something obvious.

Any constructive criticism, feedback and/or information, tips to improve the performance are welcome.

On our computers (Intel i7-2600, CPU @ 3.40, Ge Force GT 220) we render 100000 objects at about 6-8 frames/sec.
1000000 objects at 3 frames/sec.

It would be nice to improve the performance to get close to 20-25 frames/sec, although it might simply not be possible.


General Info:

Use your left mouse button to rotate the camera and A, D, W, S to move it to the left, right, up or down.

[color=#0000ff]EDIT: What we are looking is a way to improve the performance. Is our approach a proper way to render 100000 objects? We tested a lot of different ways and the reason why we chose this solution is because it gave us the best overall performance, but as I said, maybe we missed the obvious and did not use the "standard" OpenGL way of solving this problem. We couldnt really find a lot information about a project where the requirements were to render this amount of objects.

Share this post


Link to post
Share on other sites
Advertisement
* The [font=courier new,courier,monospace]Cube[/font] and [font=courier new,courier,monospace]Pyramid[/font] classes seem to be exact duplicates of each other? These classes seem like they shouldn't exist, and you should just use [font=courier new,courier,monospace]Shape[/font] instead for both? I mean, if you've got artists making all sorts of shapes for your game, you don't want a programmer to have to make classes for [font=courier new,courier,monospace]Fish[/font], [font=courier new,courier,monospace]Rock[/font], [font=courier new,courier,monospace]BiggerRock[/font], [font=courier new,courier,monospace]FencePost[/font], [font=courier new,courier,monospace]GreenFencePost[/font], [font=courier new,courier,monospace]Tree01[/font], [font=courier new,courier,monospace]Tree02[/font], etc... You should be able to add new "shapes" to a game without writing new code.

* The use of [font=courier new,courier,monospace]virtual[/font] for drawing pyramids/cubes is an unnecessary idea - especially when every odd/even shape alternates between a pyramid and a cube, as this causes your render loop to alternate between calling two different rendering functions (doubling your icache requirements).

* There's a lot of room to reduce the number of [font=courier new,courier,monospace]gl[/font] calls during rendering -- e.g. if several cubes were rendered after one another, then only the first would have to call [font=courier new,courier,monospace]glBindVertexArray[/font], every following cube could skip that call.

* There's no sorting of the data going on. By sorting your (visible) objects each frame before submitting their [font=courier new,courier,monospace]gl[/font] calls, you can greatly reduce the number of [font=courier new,courier,monospace]gl[/font] calls that need to be made (as above).

Regarding C++ style - your classes don't follow the rule of three nor implement the non-copyable idiom, which makes them dangerous:{
ShapeType x(1), y(2);
y = x;
}//Heap corruption: both x and y delete x's resources in their destructor. Also: y's resources are leaked.

Share this post


Link to post
Share on other sites
* The [font=courier new,courier,monospace]Cube[/font] and [font=courier new,courier,monospace]Pyramid[/font] classes seem to be exact duplicates of each other? These classes seem like they shouldn't exist, and you should just use [font=courier new,courier,monospace]Shape[/font] instead for both? I mean, if you've got artists making all sorts of shapes for your game, you don't want a programmer to have to make classes for [font=courier new,courier,monospace]Fish[/font], [font=courier new,courier,monospace]Rock[/font], [font=courier new,courier,monospace]BiggerRock[/font], [font=courier new,courier,monospace]FencePost[/font], [font=courier new,courier,monospace]GreenFencePost[/font], [font=courier new,courier,monospace]Tree01[/font], [font=courier new,courier,monospace]Tree02[/font], etc... You should be able to add new "shapes" to a game without writing new code.

[color=#0000ff]In this example you are right, but for us it is essential that different objects have different render methods.
[color=#0000ff]Maybe we should have explained it better in the post description.

* The use of [font=courier new,courier,monospace]virtual[/font] for drawing pyramids/cubes is an unnecessary idea - especially when every odd/even shape alternates between a pyramid and a cube, as this causes your render loop to alternate between calling two different rendering functions (doubling your icache requirements).

[color=#0000ff]The use of virtual is also necessary to be able to have 1 list of shapes and we need polymorphism for more complex object structures.
[color=#0000ff]The instantiation of shapes in the odd/even way was only done for the purpose of this test project. We will have a list of unsorted objects.

* There's a lot of room to reduce the number of [font=courier new,courier,monospace]gl[/font] calls during rendering -- e.g. if several cubes were rendered after one another, then only the first would have to call [font=courier new,courier,monospace]glBindVertexArray[/font], every following cube could skip that call.

[color=#0000ff]This is a good idea, but in the tests we have made we didnt see any relevant improvements. For instance if create only Cube objects, delete the glBindVertexArray calls in the render method of the cube and put the glBindVertexArray call in the DrawScene method, like this:

[color=#a52a2a][size=2]void DrawScene(void)
{
glUseProgram(ShaderIds[0]);
glBindVertexArray(CubeShapeType->stBufferIds[0]);

for(int id = 0; id < arrShapesSize; id++)
{
arrShapes[id]->Render(globalShapeRenderingCounter, ModelMatrixUniformLocation, ColorUniformLocation, ChangeColorUniformLocation);
}

glUseProgram(0);

globalShapeRenderingCounter++;
if (globalShapeRenderingCounter > arrShapesSize) { globalShapeRenderingCounter = 0; }

glBindVertexArray(0);
}

[color=#0000ff]we couldnt see any essential improvements.

* There's no sorting of the data going on. By sorting your (visible) objects each frame before submitting their [font=courier new,courier,monospace]gl[/font] calls, you can greatly reduce the number of [font=courier new,courier,monospace]gl[/font] calls that need to be made (as above).

[color=#0000ff]we do check if objects are visible or not (Frustum method).

Regarding C++ style - your classes don't follow the rule of three nor implement the non-copyable idiom, which makes them dangerous:
{
ShapeType x(1), y(2);
y = x;
}//Heap corruption: both x and y delete x's resources in their destructor. Also: y's resources are leaked.

[color=#0000ff]Thanks for this, we will implement it.

Share this post


Link to post
Share on other sites
I agree with Hogman about your class structure, but for slightly different reasons.

I've changed my thinking on class structures over the years and on a relatively large project I now find the base class/derived-class with render method to be unwieldy. It doesn't scale well. The best method is to define a class called shape, and for that class to encapsulate the data needed to draw any shape, i.e. a set of vertices and so on. Then you can separate your data from the rendering of that data, perhaps using a visitor pattern to fetch and render all shapes from a collection of shapes. No virtual functions required and more flexibility in the design. You tend to find with base class/derived class that there are often things that two derived classes need that a third doesn't, that get stuffed into the base class in any case. It just grows into a bit of a mess with the lines of responsibility unclear once you start adding lots of derived classes.

With respect to drawing 100,000 objects, you really need to be instancing.

Share this post


Link to post
Share on other sites
This might provide some insight: http://origin-developer.nvidia.com/docs/IO/8230/BatchBatchBatch.pdf?q=docs/IO/8230/BatchBatchBatch.pdf

As mentioned above, it's not feasible to be submitting 100,000 different draw-calls per frame. You need to merge draw-calls together in order to reduce the CPU load.
If instancing is not an option, there's many "pseudo instancing" techniques - such as storing the same vertex data several times back-to-back in the same VBO, which lets you draw the same object multiple times with one draw-call.

In this example you are right, but for us it is essential that different objects have different render methods.
The use of virtual is also necessary to be able to have 1 list of shapes and we need polymorphism for more complex object structures.
Your low-level rendering classes, which make [font=courier new,courier,monospace]gl[/font] calls, do not need to have polymorphic render functions. At this level, you should be working with simple objects which can be composed into complex objects.
At a higher level, you can have polymorphic classes which submit different combinations of these simple compositions.
This is a good idea, but in the tests we have made we didnt see any relevant improvements.
Have you confirmed weather you are GPU-bound or CPU-bound? e.g. if your CPU loop takes 30ms, but is submitting 60ms worth of work to the GPU, then no amount of CPU-side optimisation is going to improve performance.

* There's no sorting of the data going on. By sorting your (visible) objects each frame before submitting their [font=courier new,courier,monospace]gl[/font] calls, you can greatly reduce the number of [font=courier new,courier,monospace]gl[/font] calls that need to be made (as above).
we do check if objects are visible or not (Frustum method).
Visibility testing is not sorting. After you've culled your scene and determined the visible list of objects, you can re-order the list of objects to be drawn to achieve the most optimal rendering order.
e.g. if you've got expensive pixel shaders, then drawing objects from the closest the the furthest will improve your GPU performance (due to hi-z / early-z pixel rejection).
Or, if you've got many objects that share the same state (e.g. same textures, same shaders, etc) then drawing them at the same time will reduce the number of [font=courier new,courier,monospace]gl[/font] calls, which will improve CPU performance.

Also, have you run your program through any kind of profiler to see where the hot spots are?

Share this post


Link to post
Share on other sites
Sign in to follow this  

  • Advertisement