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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0
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2answers
33 views

Render specific part of a texture in OpenGL (2D Sprite Sheet)

I've looked at this answer to find out how to render just a part of a texture: http://stackoverflow.com/questions/6884285/c-opengl-render-part-of-an-image I tried that, but the problem is, this is how ...
0
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0answers
29 views

Octree Frustrum Culling

times came when i had to implement some culling into my engine. I started by reading some stuff and so far so good. I managed to create an octree which can effectivly divide my geometry's vertices ...
0
votes
1answer
203 views

Trying to implement Camera

I'm trying to implement a Camera class in order to walk and look on the world as follow: #ifndef _CAMERA_H_ #define _CAMERA_H_ #include <glm\glm.hpp> class Camera { public: Camera(); ...
0
votes
1answer
101 views

Small text is very light / faint with FreeType and OpenGL

I'm able to render large text with FreeType just fine: But when I want to render small text (and the only parameter that changes is the font size), the quality is much poorer: As you can see, ...
0
votes
1answer
479 views

OpenGL Tessellation makes point

A little problem with my tessellation shader. I try to implement a simple tessellation shader but it only makes points. Here's my vertex shader : out vec4 ecPosition; out vec3 ecNormal; void ...
0
votes
1answer
95 views

Java OpenGL Perspective matrix not working

I'm trying to render a simple triangle with OpenGL in Java using LWJGL3. Everything is working great, but the projection matrix (perspective) is not working. In C++ I just used to apply the ...
1
vote
0answers
18 views

Vbo 3d triangle opengl w/ LWJGL

So i am using lwjgl, took me about 4 hours of hard work to achieve triangle rendering and vbos, now i want to render a triangle in 3d space. I know you have to use projection matrices. But when i have ...
5
votes
4answers
4k views

Can't understand these UV texture coordinates (range is NOT 0.0 to 1.0)

I am trying to draw a simple 3D object generated by Google SketchUp 8 Pro onto my WebGL app, the model is a simple cylinder. I opened the exported file and copied the vertices positions, indices, ...
0
votes
1answer
16 views

Using glm to rotate the modelview matrix based on the cursor position

I am rendering a 3D model of an object, and I want the user to be able to rotate around that object by dragging the mouse. To do this, I want to use the cursor position to continually update the ...
0
votes
1answer
112 views

How to Load a Level for use with the Bullet Physics Library

I am trying to use a level in .obj format loaded with Assimp to generate a btBvhTriangleMeshShape to use with the Bullet physics library. I can successfully load btConvexHullShapes as well ...
5
votes
2answers
341 views

Multithreaded Game Loop

I'm trying to implement a multithreaded game loop. I already did that but had to use a few locks for that, which ruined the performance. After researching a bit I came up with this idea: Instead of ...
0
votes
1answer
99 views

How to clip or mask entity in adnroid/andengine?

I want to implement masking with sprite in Andengine. I want same functionality as in ios class called SKCropNode which works like an masking node! Is there any workaround like this in ...
0
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0answers
20 views

OpenGL Black rectangle in rendering texture

I create textures (for example, I just fill the texture color), and render their. But, for some reason, to the upper edge added black rectangle. Screenshot: var Textures: array of GLuint; ...
2
votes
0answers
37 views

equirectangular panorama rendering?

I want to render my scenes as equirectangular panorama frames. I can get the angular fisheye which is what I actually need by applying the rendered frame as a texture to a correctly UV mapped circle. ...
2
votes
0answers
25 views

OpenGL Depth Cubemap with Geometry Shader Not Rendering Correctly

I was having some trouble with cubemaps in OpenGL, and was hoping to get some help. I've been following a tutorial about point light shadow mapping using cubemaps, where a geometry shader is used to ...
0
votes
0answers
79 views

How do I extract the right information from my projection matrix for frustum culling?

I've tried several different tutorials for Frustum culling, however I cannot understand them. Here's my function that sets up my projection matrix (someone else helped me with this, but I don't know ...
23
votes
5answers
16k views

How to avoid texture bleeding in a texture atlas?

In my game there is a Minecraft-like terrain made out of cubes. I generate a vertex buffer from the voxel data and use a texture atlas for looks of different blocks: The problem is that the texture ...
0
votes
1answer
45 views

How to wrap textures inside shader GLSL

I'm trying out GLSL and one of the problems I'm facing is wrapping a random texture sampler in the shader. Searching for answers on the web first, this leads me to using these commands: ...
1
vote
1answer
52 views

Instanced rendering with ARB_vertex_attrib_binding

I'm trying to separate the vertex format specification from the vertex data. I was able to do that for the mesh vertices successfully. For instanced rendering I wanted to further separate the instance ...
0
votes
0answers
17 views

Trouble texturing isometric tiles with tilesheet: OpenGL

I don't know if I am just... not seeing something here. I have been working on this for quite some time trying to get it functioning. I have used sprite sheets and texture coordinates before - so I am ...
1
vote
1answer
29 views

How to correctly specify the offset in a call to glVertexAttribPointer()?

I'm trying to draw a simple triangle using the following vertices: std::vector<VertexFormat> vertices; vertices.push_back(VertexFormat(glm::vec3(0.25, -0.25, 0.0), glm::vec4(1, 0, 0, 1))); ...
1
vote
1answer
52 views

Greedy Mesh generation for a voxel-based game

EDIT: I have already found my problem and fixed it (but I cant accept my own answer for another 2 days) I'm currently making a 3D voxel-based game and now that I have started optimising some aspects ...
0
votes
1answer
41 views

Beginning on animations

I am clueless with regards to animations. I have a simple rendering engine that renders models, sprites, skyboxes and whatnot; but everything is simply static with no animations whatsoever. With my ...
1
vote
1answer
205 views

SDL & OpenGL - Artifacts when multisampling

Im trying to render a model with anialiasing using OpenGL and SDL, but when I do I get strange artifacts. When I render with antialiasing disabled everything looks fine. When antialiasing is ...
0
votes
0answers
30 views

Set Render Target usage

I am using Unity and I have some difficulties about understanding the way Set Render Target works and how it can behave with the shaders. Is it possible to render a shader pass in multiple render ...
1
vote
1answer
869 views

How can I prevent the viewport from stretching/distorting?

Basically, I want to know how I can remove distortion or stretching of the rendered image when the viewport/window size changes. The following images exemplify the distortion/stretching I'm talking ...
3
votes
2answers
149 views

How do I pick tiles from an isometric map with slopes?

I'm looking for a way to convert mouse/screen coordinates to isometric map coordinates, with the addition that the world has slopes and cliffs, and I have to be able to tell which quadrant of the tile ...
0
votes
2answers
89 views

Fragment shader compiling in webGL but not in OpenGL

I am programming in Haxe (language compiling to multiple platforms) and I have written some shaders. My fragment shader runs fine in html5, but when I try to compile for native (OS X and/or Neko, a ...
0
votes
0answers
7 views

Using AWT with LWJGL on OS X

The VM argument -XstartOnFirstThread is required for LWJGL to work on OS X. Anything in the java.awt package freezes the JVM when used with the VM argument -XstartOnFirstThread. E.g. ...
3
votes
1answer
340 views

Using textureGrad for anisotropic integration approximation

I'm trying to develop a real time rendering method using real time acquired envmap (cubemap) for lightning. This implies that my envmap can change as often as every frame and I therefore cannot use ...
1
vote
3answers
43 views

OpenGL, GLSL, Modify Background Fill via Fragment Shader

I have noticed that fragments rendered by the glClearColor() method do not pass through shaders. However, I'd like to modify these fragments using my fragment shader. Is there any way of forcing them ...
1
vote
0answers
10 views

OpenGL (lwjgl) Frame Buffer Object GL_COLOR_ATTACHMENT Not Being Written To

I am currently developing a deferred renderer for my game engine and I have to output multiple textures from my shader to my GBuffer. I have been struggling with getting multiple outputs from the ...
4
votes
5answers
295 views

How can I render “two-sided” clouds like in Minecraft?

The clouds in Minecraft are semi-transparent and are rendered on both sides. If you fly into the cloud you can see inside of the cloud. If I render clouds the inside faces would be visible on the ...
7
votes
2answers
694 views

How can I debug _why_ glDrawArrays is very slow?

I'm working on a game that uses CEGUI and Ogre. Recently, we've discovered that some of our customers with GeForce4 MX 4000's, performance is terrible. After a night spent debugging, I've tracked ...
0
votes
0answers
12 views

Using gl3w and Win32 api, without glut

I'm still a beginner, the example on skaslev's site require us to use glut as an interface to create a window. For some reason, I'm required to create a window purely with Win32 api, but I am not ...
0
votes
0answers
52 views

OpenGL strange lighting/model problem

I've made a .obj reader in c++ and I've tried rendering some models. I've got the whole concept from here: ...
1
vote
1answer
66 views

Android OpenGL EGL context lost

I'm developing simple Android game in OpenGL ES 2.0 and the development stage is getting closer to publishing game on play store, but I'm still unsure about EGL context behaviour on different devices. ...
0
votes
0answers
60 views

How to calculate spherical harmonic coefficients for indirect diffuse?

After reading the article "An Efficient Representation for Irradiance Environment Maps", I'm a bit confused as how to calculate the spherical harmonic coefficients. I'd like to generate these ...
0
votes
1answer
201 views

DirectX11 Equivalent of OpenGL code

I am currently porting parts of my engine over to D3D11 from OpenGL and was trying to figure out how I would accomplish the following blending functions in D3D11. glEnable(GL_BLEND); ...
0
votes
2answers
125 views

GL_SPOT_CUTOFF not working properly

I'm new to OpenGL. I'm studying OpenGL 2.1 and I'm trying to make a little program to test the GL_SPOT_CUTOFF property, but when I set a value between 0.0-90.0, the light doesn't work and everything ...
0
votes
1answer
54 views

Raypicking / raytracing in OpenGL

Alright, so before you down vote saying that OpenGL doesn't support rays for rendering, please read: So I want to detect a quad in opengl 1.1( I don't want to use opengl 3.0). I wanted to detect it ...
1
vote
2answers
157 views

OpenGL Vertex Array Object(VAO)

I have drawn a triangle and a square using open gl and everything was fine. I have then tried to draw the same triangle and square, while implementing VAO's and now I only get a white triangle - ...
0
votes
1answer
29 views

Open GL: How to map point inside frustrum to normal device coordinates (NDC)?

I read this article http://www.songho.ca/opengl/gl_projectionmatrix.html. It's explain how calculate projection matrix coefficients. But I completely can't understand how author perform mapping from ...
4
votes
1answer
2k views

What advantages does multisampling have over supersampling?

I never really fully understood this, or found an article which explained all the steps in a friendly way. I'll start with what I do know already (which I hope do not contain misconceptions). I'm ...
17
votes
3answers
14k views

How do I implement anti-aliasing in OpenGL?

I want to do full-screen anti-aliasing in OpenGL, and dont want to use the anti-aliasing that is provided by OpenGL itself, since I am building a game and want good effects in it. How should I ...
5
votes
3answers
627 views

Should I implement anti-aliasing by rendering large and scaling down?

Having read about anti-aliasing, I came to realise that I could render my scene 8× the original size of the screen, then shrink it to render it on my original screen to improve the effect that I have ...
0
votes
1answer
94 views

Incorrect Normal Matrix

In my game engine I'm passing a normal matrix to my shaders like so: Matrix3f normalMatrix = modelMatrix.invert().transpose(); However this is causing lighting to rotate with my object, producing a ...
55
votes
3answers
12k views

What is Vulkan and how does it differ from OpenGL?

Khronos Group (the standards body behind OpenGL) has just announced Vulkan: Vulkan is the new generation, open standard API for high-efficiency access to graphics and compute on modern GPUs. This ...
0
votes
1answer
31 views

Can't draw lines in 2D space with GLFW and OpenGL

I'm trying to draw a grid in 2D space using GLFW and OpenGL but for some reason I only get this on the screen: Here's my code: #include <GLFW/glfw3.h> #include <stdlib.h> #include ...
1
vote
1answer
162 views

Problems with texture orientation in space

I am currently drawing texture in 3D space and have some problems with it's orientation. I'd like me textures always to be oriented with front face to user. My desirable result looks like ...