OpenGL is a graphics standard and API which targets the desktop and workstation markets. It is designed to be easy to accelerate with dedicated computer hardware, and hence most implementations give greatly improved performance over traditional software rendering. Currently, OpenGL is used for ...

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30 views

Open gl blending problem c++

im creating project from nearly scratch in c++.. i created skybox and terrain . the result is catastrophic ! the terrain goes away and the ground also goes away,i dont know why ! i tried to disable ...
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33 views

glOrtho and VBO

I'm trying to send triangles to OpenGL using screen coordinates. Using the deprecated glBegin and glEnd I could just set up an orthographic projection and use screen-space coordinates as the ...
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1answer
78 views

C++: from LWJGL to C++ with OpenGL

I've been trying my best on porting my 3D game from Java to C++, but to no avail. I use only LWJGL with OpenGL but I cannot find any other library in C++ that supports as much as LWJGL does for Java. ...
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2answers
73 views

How do game engines manage to 'detect' the opengl supported in a computer

I am learning OpenGL 3.3 and OpenGL 2.1. I want to make a game engine with both. So far I can do advanced stuff with both of them. I noticed that graphics engines like Irrlicht support OpenGL 1.x to ...
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1answer
63 views

Issue with detecting collisions in Pong

I've been working on making Pong in OpenGL and SDL and currently have both paddles and the game ball set up properly. I have an Object (or Entity) class which is used to instantiate each of the ...
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1answer
45 views

OpenGL dynamic font glyph cache library

I have begun work on an OpenGL application (all on my own and with little knowledge) and started with FTGL, rendering true type fonts, which, with alot of text has a great impact on frames per second. ...
3
votes
1answer
93 views

Mesh's triangles don't move properly during skeletal animation

I've been trying to implement skeletal animation in my engine using this tutorial, and I've been having problems. Using the model they provided, I get results like this: But on some other models, ...
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0answers
54 views

Front Face Culling with Shadowmapping

To avoid shadow acne I usualy use front face culling which works great. But for my current implementation the mesh is a quite complex terrain (depending on the lod level) and than the shading (dot ...
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1answer
122 views

Performance of glDrawElements vs glDrawRangeElements vs glDrawArrays

I've looked around on the web trying to find a good answer to this, but am unable to find one. Different forums mention driver bugs and the likes, but these discussions are usually almost 10 years ...
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1answer
131 views

SDL2, OpenGL, Nvidia laptop screen tearing

EDIT 2016-03-06. Note 1: Apparently this is a known issue with Nvidia. If you've found here due to same problem, please stoke the collective "please fix it" by filing a "question" at ...
4
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0answers
98 views

Windows vs OSX Performance with SDL, OpenGL [closed]

I have been writing an SDL OpenGL game in c++ for a couple of years now, writing my own engine for the most part (using Box2d for physics). I'm primarily a mac user, so I've been using xCode to write ...
1
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1answer
84 views

OpenGL Applications Bring computer to halt

Whenever I run any application that utilizes the OpenGL interface, my entire computer comes to a halt, but it doesn't do this when it utilizes the DirectX interface. I run both Linux (Ubuntu 15.10) ...
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1answer
40 views

[opengl]get world position after rotate object by pivot

I need to rotate an object around a pivot,so I use this theory: Translate the object to Pivot position Rotate the object Translate back the object from Pivot position everything works fine,I can ...
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1answer
38 views

OpenGL - Quad is being separated like a two triangles after blending

I wanted to add transparency for my UI elements, so I enabled blending by adding: glEnable(GL_BLEND); glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA); before renderer and glDisable(GL_BLEND); ...
0
votes
1answer
63 views

OpenGL texture 2d array won't render with depth > 1

Below code uploads my texture memory that's described in the passed parameters. When 'vPixelData' only holds 1 item/texture it is rendered properly, but once there's 2 or more nothing shows up. ...
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0answers
33 views

How do I implement a LWJGL orthogonal matrix?

As seen on the official LWJGL page, I tried. But failed. All the things I've found on SO and other sites didn't answer anything that had to do with this specifically. I've been on this for weeks. It's ...
0
votes
1answer
59 views

OpenGL GLSL vector of sampler2D

If im trying to create an obj. file loader in c++ and draw it with opengl i need to use multiple textures in the fragment shader.I know i can just use: `uniform sampler2D Texture1` `uniform ...
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0answers
49 views

How to copy texture of type GL_TEXTURE_EXTERNAL_OES to a texture of type GL_TEXTURE_2D

How to copy texture of type GL_TEXTURE_EXTERNAL_OES to a texture of type GL_TEXTURE_2D ? How to find the internal format of texture ?
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1answer
54 views

How do I calculate a vertex's position on the CPU?

I'm creating light processor and I need light position and vertex position after translating, rotating and scaling (to calculate distance between them to check if light is affecting my vertex ...
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1answer
85 views

C++ & OpenGL - Bad orthographic projection matrix?

So I'm trying to render 2D text in my Game Engine using programmable pipeline. Normally I'm using perspective projection matrix but for UI elements I'm trying to create orthographic projection matrix ...
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1answer
24 views

Should I add error handling to SDL_GL_SetAttribute?

As the title says, I wonder if I should handle errors for : SDL_GL_SetAttribute Can it actually fail to set? And if it can, what could be a reason for it to fail?
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vote
1answer
92 views

OpenGL Arc-Ball Camera Yaw Pitch GLM::Rotate

I'm currently working on a small Voxel-Editor Project. In the editor, I plan on using an Arc-Ball camera which rotate around the model. My camera is currently working but in an odd way. I can't seem ...
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3answers
81 views

OpenGL Colour Issues

I am using a single VBO to store vertices in the follow format: v1X, v1Y, v1Z, v1R, v1G, v1B, v2A, v2X, ... Vertex positioning is fine, shapes show up where expected, however instead of using the ...
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1answer
105 views

Modern OpenGL c++ obj loader

So i made a obj loader in c++.I used blender to export my files. I tried to draw 2 squares(one perpendicular to the other) and when im looking at them from above some weird black triangles apear, ...
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votes
2answers
42 views

Using VBO in Opengl. powered with c# TAOFramwork

I'm doing a 3D display for a big object. I've managed to display it with opengl primitives, so it's (very) slow Now i want to use the VBO optimization. But when i lost the focus on the opengl window ...
7
votes
1answer
127 views

Depth Peeling implementation problem: How to render the next layer? (OpenGL)

I try to implement order-independet transparency sticking to the pseudo code in the linked paper (page 4). I can't figure out how they are able to do this in OpenGL. I am rendering the scene two ...
0
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1answer
52 views

C++ OpenGL More textured objects equals less FPS

So I'm creating a game engine with many features, last time I focused on textures. When I finished implementing some new code (Made by myself) I created new Entity with texture, and it was working ...
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0answers
72 views

Modern OpenGL and SpriteBatching

I tried to find tutorials regarding SpriteBatch done in Modern OpenGL 3.0+, but failed to find any good resources so far. So can anybody please provide me a good resource/tutorial to achieve ...
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votes
2answers
166 views

How do you define and draw rectangles in OpenGL?

I am very new to OpenGL and I am not sure one the basis of how to create and draw objects. So how would I draw simple rectangles in a window using OpenGL? My understanding is that I need to define an ...
0
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0answers
34 views

Disable OpenGL NVidia Driver Optimization During Development

I've noticed while looking at gDebugger that sometimes what I dispatch as draw calls never actually show up in the logger. I assume that there is some driver level optimization going on here; so is ...
0
votes
2answers
180 views

Modern OpenGL project in c++ .obj loader

I want to create a class in c++ that loads a model with the obj format.The model gets generated from Blender(3D modeling program).When i try do draw something on the screen without the class(all the ...
0
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0answers
80 views

A 2D card game using OpenGL

I am creating a 2d card game. I have written the low-level functions, game logic, game algorithms in C++. I now have to create a graphics layer that the player can interact with. This just has to be ...
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0answers
33 views

Issue with Use SSBO OpenGL

Students that use OpenGL. Do not speak English well. So please understand. There is currently a problem C++ Code Setup() : glGenBuffers(1, &ssboHandle); GLuint ssbo_binding_point_index = 0; ...
5
votes
2answers
295 views

How to render water reflections on multiple heights

I'm making a voxel game on OpenGL, and are trying to find a way to render semi-realistic water (At least partially good looking, it doesn't need to be strictly scientific accurate). All sources ...
1
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0answers
40 views

Cell height with heightmap for collision detection

Hello everyone I'm programming a game with c++ and openGL. My world is generated from a heightmap (100x100 matrix with values 0-255) and now I need a function that returns the actual height based on ...
0
votes
0answers
50 views

Wrong Normal When Models is Close to Each Other

I have a problem regarding my Normal FrameBuffer that creates gaps between models. The image below contains 10x2x10 block (Minecraft style) and one character. The image is outputed through: ...
1
vote
2answers
109 views

How to combine depth and stencil tests?

I have a continuous height-mapped mesh to represent landscape. I use the stencil test to create holes in the mesh. I draw holes to the stencil buffer and then use it to discard mesh fragments. ...
4
votes
1answer
112 views

SSAO issue - surfaces darken based on camera angle

I have a strange issue in my engine where my SSAO effect will extremely darken or lighten based on my camera angle: In that example, I'm just outputting the ssao texture to the screen. The texture ...
0
votes
1answer
109 views

How could we use trigonometry for moving around a 3D World?

Well I have a question about geometry and 3-Dimensional player movement in general. I'm using Java, OpenGL and LWJGL. This is basically what I got: currentFrontSpeed: Is a float that contains the ...
1
vote
1answer
138 views

Implementing Shadow Mapping in Python and OpenGL 2.1

I am trying to create a little shadow mapping demo. My code is currently divided into three rendering passes: Pass 1 - Create the depth texture that will be used for shadow mapping on an offscreen ...
3
votes
0answers
62 views

How do I align the cube in which shadows are computed with the view frustrum? (“View Space aligned frustum”)

Short and concise: Given 8 world space positions that form a cube of arbitrary size, position and orientation and given an arbitrary light direction. How do I compute the View and Projection matrix ...
0
votes
0answers
29 views

Failed to understand how to use glm::unProject (OpenGL 4.3)

Situation: I use OpenGL 4.3, FreeGLUT 3.0, and GLM library. Let say i have a simple 2D object (a ball) and it moves accordingly to the simple equations: x = x_0 + v_0 * t * cosf(alpha); y = y_0 + ...
0
votes
1answer
68 views

Image rendering with additional space around it

When I try to display an image that is 400 pixels wide and 800 pixels high, it is not displayed this way. Instead it is diplayed like this: Instead it is displayed like this You can see at the bottom ...
0
votes
0answers
67 views

How to dynamically draw a filled polygon with a given array of vertices?

Say I have a simple array of vertices (or floats with every odd index being the X of a vertex and every even being the Y), how could I paint all the area between the vertices? As in, I have maybe ...
1
vote
1answer
77 views

OpenGL App not setting cursor position appropriately

I have written a small application using OpenGL, and have implemented some rudimentary camera controls. Unfortunately, I cannot get the application to set my cursor position correctly. The cursor is ...
0
votes
1answer
71 views

Fragment shader, tint color problem

I am new to shaders, and I am trying to tint a texture to mark status of a enemy. I am implementing shaders on OpenGL ES 2.0 (Mobile) The problem is that with this shaders, I see the enemy without ...
0
votes
1answer
74 views

Aspect ratio of drawn quad messed up after rotating

When I draw a quad that is rotating the aspect ratio of the quad gets messed up and the size changes. Gif of what is happening I am confident it has something to do with the way I calculate the size ...
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votes
1answer
33 views

OpenGL/GLSL matrix in uniform block confusion

I'm a bit confused about the proper way to send a matrix from my code (C++) into a GLSL shader. My matrix object is stored in row major format in memory. If I use the following shader code it works ...
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0answers
26 views

Drawing Ray from ray picking is not working correctly

I have been implementing ray picking to select squares in my opengl program. I tried to follow this post I found http://gamedev.stackexchange.com/questions/109579/algorithm-for-triangle-picking after ...
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votes
2answers
161 views

C++ Multi-Platform (Windows, Linux, Android) OpenGL(ES) Solutions or Tutorials? [closed]

I'm sorry if this has been asked recently and I'm not Googling it right, but I've been digging all week for something. I've got a game prototype I made in Unity, and I have some decent experience ...