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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52 views

Performance differences when it comes to dynamic vector graphic between using OpenVG and OpenGL [on hold]

In my Game Engine I want to add an advanced GUI framework. It will have dynamic vector based graphic elements. Consider it similar to HTML5 and CSS3 or GTK/Qt. I could implement this via OpenGL (low ...
0
votes
1answer
67 views

Having trouble with projection matrix, need help [on hold]

I'm having trouble with what appears to be the projection matrix. Given a wide enough of a screen, when a cube is on the left and right most edge, the left or right wall will appear stretched to the ...
4
votes
5answers
5k views

openGL book recommendation [on hold]

I wanna start learning OpenGL especially for android game programming but I would eventually want to be able to use this knowledge for windows\linux as well. I'm having difficulty choosing between ...
0
votes
0answers
17 views

Camera Rolling when Implementing Pitch and Yaw

I am implementing a camera in opengl for an android game and am having problems getting the pitch/yaw/roll of the camera correct. I have read many tutorials on quaternions and have implemented a basic ...
0
votes
1answer
60 views

Per vertex diffuse lighting not propogating across entire model

I'm not sure how to describe this problem so I've added a picture. When I add per vertex diffuse lighting to my model (just a field of cubes for simplicity) the lighting effect applies to each ...
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0answers
23 views

Artoolkit, transform pixels coordinates to be aligned to the marker

I'm working with artoolkit, i was trying to get the marker pixels using dataptr and marker_info (x,y coordinate), then i used opengl (GL_POINTS) to draw on these pixels and that was working right in ...
0
votes
0answers
14 views

How to load and render PhysX 3.3 heightfield

I'm trying to load a PhysX 3.3 heightmap and render it with OpenGL using glm and glfw, but so far it doesn't seem to be working. I'm basing my code on the PhysX samples, and am also using FreeImage to ...
1
vote
1answer
58 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 ...
0
votes
0answers
33 views

OpenGL: What's the best way to convert a screen coordinate to a world coordinate? [duplicate]

For example, suppose I'm building a first-person shooter and the player pulls the trigger. I want to convert the screen coordinate (x, y) into a world coordinate (x, y, z) to know what they've hit. ...
3
votes
1answer
252 views

small independent game development on a virtual machine

I've been learning about OpenGL and SFML with c++ now for about 6-8 months, and would like to work on a small little personal game to put some of my skills to the test. Now I want to kill two birds ...
3
votes
2answers
147 views

Shader - Calculate depth relative to Object

I am trying to calculate depth relative to the object.Here is a good solution to retrieve depth relative to camera : Depth as distance to camera plane in GLSL varying float distToCamera; void main() ...
1
vote
1answer
182 views

Render 2 images that uses different shaders

Based on the giawa/nehe tutorials, how can I render 2 images with different shaders. I'm pretty new to OpenGl and shaders so I'm not completely sure whats happening in my code, but I think the shaders ...
1
vote
1answer
47 views

What is the relationship between glVertexAttribPointer index and GLSL location?

I've been getting some strange results when trying to implement a normals buffer for the purpose of rendering lighting. It seems to be related to the indexes for glEnableVertexAttribArray, ...
1
vote
0answers
31 views

Variance shadow maps less blurred than normal shadow map

I've implemented VSM (and also ESM) in my engine but results are for me not as I expected and saw in many examples published on network. I set filtering of shadow maps to GL_LINEAR but when I compare ...
1
vote
0answers
38 views

Shadow map shimmering, indexing outside the shadow map

I have tried to reduce shadow shimmering/flickering using technique described here: http://msdn.microsoft.com/en-us/library/windows/desktop/ee416324%28v=vs.85%29.aspx I works as I want and shimmering ...
1
vote
0answers
44 views

Easy way to set face colors with indexed VBOs?

I'm loading OBJs, which lend themselves well to setting up as indexed VBOs, since each vertex is only defined once and then a face definition will reference the same vertex more than once when they ...
1
vote
1answer
63 views

IBO interfering with VBO data?

I have a vertex and color VBO that render a plane (2 triangles) just fine. However, when I attempt to use an IBO to render the plane, the vertices are completely off. My nice square looks all crumpled ...
2
votes
1answer
83 views

How to share values between different shader programs?

I am using Unity but this might concerns all type of shaders. I would like to know if this is possible to share values between different shader pass.Let's imagine that I am computing something in the ...
4
votes
1answer
798 views

exporting bind and keyframe bone poses from blender to use in OpenGL

EDIT: I decided to reformulate the question in much simpler terms to see if someone can give me a hand with this. Basically, I'm exporting meshes, skeletons and actions from blender into an engine ...
0
votes
0answers
63 views

Garbaged textures on OpenGL [closed]

I've been struggling with this for a long time, and now I've hit a dead-end, I have no idea what to do. I'm pretty new to OpenGL (roughly about eight months), and I've been developing an engine for ...
1
vote
1answer
77 views

Correct multiplication order for a 2D Matrix

I'm currently trying to create a camera and entity/model matrix for my 2D game similar to that of Unity3D. I've already tried to find answers to this question on stackoverflow/gamedev but i couldn't ...
0
votes
1answer
30 views

Using IBO's with color

I am trying to familiarize myself with IBO's by drawing triangles etc but I'm finding no way to get the color to apply properly. Can I not use an IBO to index the color values as well? I am having ...
0
votes
1answer
78 views

OpenGL / Soil Image Loading Difficulties [closed]

The Problem I am attempting to load and display an image in OpenGL using the SOIL library. I originally started with lodePNG but I had difficulties getting the image to display so I assumed it was ...
1
vote
1answer
233 views

Calculating shadowmap coordinates for cubemap in shading pass?

I'm trying to implement shadow mapping with cube maps. I believe I've done the first stage by filling the cube map, but for the final shading pass I am unsure how to exactly calculate the cubemap ...
0
votes
0answers
74 views

What is the mathematics behind real time rendering? [closed]

I know that movie rendering uses non-real time rendering techniques that requires a lot of time to render some seconds of video, because it uses the ray tracing technique that simulates the real world ...
2
votes
1answer
152 views

Use different values for Depth Test and Depth Write in OpenGL

Is there a way to use something similar to PolygonOffset to make a depth test more permissive (move fragment depth towards eye) but still write the original depth value to the depth buffer? The only ...
-1
votes
0answers
23 views

How difficult is to port a Cocos2D-iPhone game to Android AndEngine? [closed]

I'm considering to develop a new game for iOS using Cocos2D. If the app shows good results, I want to port it to Android. I have a few options for porting it: Use apportable to port the ...
0
votes
1answer
44 views

GLSL: Vertex attribute to int

I'm trying to write a shader which renders a multitextured geometry wihout rerendering the geometry with each texture. In my test I'm not using textures, I just convert the texture index to a color ...
18
votes
5answers
2k views

Why do we use 4x4 matrices to transform things in 3D?

To translate a vector by 10 unit in the X direction, why do we have to use a matrix? We can just add 10 to the mat[0][0], and we got the same result too.
-3
votes
0answers
50 views

GLSL array with variable index? [closed]

I have a GLSL fragment shader with this part of code: for(int i = 0; i < 10; i+=3){ vec3 l_pos = vec3(lightMat * vec4(light_poses[i],light_poses[i+1],light_poses[i+2],1)); vec3 ...
2
votes
0answers
99 views

Problem with uniforms in OpenGL

I have a strange problem I can't figure out. On the CPU I have class that handles the material properties for a model. material = new Material(); material->Emissive = vec3(0.1, 0.0, 0.0); ...
0
votes
0answers
23 views

How to upload lights when doing one pass per light

Suppose I have a reasonable amount of light sources that I upload at once in my forward rendering and accumulate them in shader. Now that I am willing to move to deferred, and so one pass per light, ...
0
votes
1answer
52 views

Why does my modern OpenGL heightmap render as line segments instead of faces?

I'm brand new to OpenGL and have been trying my hand modern openGL. A few days ago, I tried to create some terrain by using a heightmap stored in a grayscale 32-bit BMP. I am using SDL 2.0, GLEW and ...
0
votes
1answer
176 views

translate-scroll repeated 2d texture using opengl shader

I managed to implement an infinite 2d texture scrolling using the following shader. btw I'm using cocos2d-x 2.2.1. The vertex shader: attribute vec4 a_position; attribute vec2 a_texCoord; #ifdef ...
1
vote
1answer
124 views

glOrtho setting view

I am duplicating this thread from stackoverflow, please remove it if that is not allowed. I'm completely new in OpenGL. I have this problem: I have quite a complicated scene, and I am looking at it ...
0
votes
0answers
35 views

Depth texture white in shader

I am trying to implement shadow mapping into my project and am stuck at this problem: If I'm reading the shadow map values with glReadPixels and linearize those values, I am getting exactly the value ...
1
vote
1answer
55 views

Selection with region (when rendering with shaders and VAO)

I am currently render my geometry using "Modern OpenGL" approach (with shaders and buffers). I have already implemented picking of single primitives using glReadPixels. Now I am faced with problem how ...
0
votes
2answers
332 views

Is this Rotation Matrix correct?

I'm having heavly troubles with setting up a View Matrix and a Projection Matrix. It simply doesnt work. So I think my problem is related to my rotationMatrix function. I'm using this tutorial to ...
1
vote
1answer
59 views

Design question: best way to model and visualize a long grid of data [closed]

Perhaps some noob questions for a scientific application that you can assist with: I am trying to render a large, evenly spaced grid of data in 2D. The full data set dimensions could be anywhere from ...
2
votes
2answers
492 views

How do I apply 2 rotations about different points to a single primitive using OpenGL

I'm working on a 2D top-down shooter game that has a rotation feature like Realm Of The Mad God such that if you press e the camera rotates around the character in a clockwise direction and q rotates ...
0
votes
3answers
66 views

Arbitrary number of VBO to Vertex Shader

I am currently using standard modern OpenGL way to render a mesh via VBO and attributes glEnableVertexAttribArray(aVertexPosition); glBindBuffer(GL_ARRAY_BUFFER, VBO); ...
1
vote
2answers
243 views

How are red dot/reflex/holographic sights implemented?

In first-person-shooters like Call of Duty, the hologram only appears when it is behind the glass portion of the sight. In OpenGL, would it be implemented by rendering the glass to the stencil buffer ...
0
votes
3answers
87 views

Can I mix the use of VAO and direct usage of glVertexAttribPointer?

Let's say I am not using VAOs. I have an array of vertex positions in memory that I want to send to the shader. I do the following (assume I have enabled the corresponding vertex attrib arrays): ...
-1
votes
0answers
34 views

Incorrect texture applied to triangle

I am trying to draw a certain part of a texture based on data from another texture. A texture is passed into the fragment shader. Its red component contains a value from 0-255 (shader maps it to 0-1) ...
0
votes
0answers
54 views

Shader - Objects Depth or Thickness

I am using Unity and would like to render the thickness of an object.My first thought was to use the ZBuffer and the depth but it is always depend to the camera, it seems legit.But I would like to ...
1
vote
1answer
69 views

libgdx glClearColor not setting right color?

i just new to libgdx and trying to understand the example code, the following code sets the bg color Gdx.gl.glClear(GL10.GL_COLOR_BUFFER_BIT); Gdx.gl.glClearColor(60,181,00,0f); my ...
3
votes
2answers
1k views

FBX Importer - Texture Name

I have a problem with the FBX SDK. I read in the data for the vertex position and the uv coordinates. It works fine, but now I want to read for each polygon to which texture it belongs, so that I can ...
3
votes
0answers
399 views

Deferred rendering and gaussian blur - artifacts

I compute Gaussian blur in two passes (horizontally and vertically). Shaders look like this: Horizontal blur - fragment shader: #version 420 layout (location = 0) out vec4 outColor; in vec2 ...
1
vote
1answer
145 views

How do I call OpenGL methods that require pointers in C#?

I have found the following C++ code in this tutorial to draw a triangle with OpenGL 4: float points[] = { 0.0f, 0.5f, 0.0f, 0.5f, -0.5f, 0.0f, -0.5f, -0.5f, 0.0f }; GLuint vbo = 0; ...
6
votes
2answers
804 views

Atmospheric scattering and sky geometry

I'm trying to implement an atmospheric scattering in my graphics (game) engine based on the GPU Gems article: link. An example implementation from that article uses a skydome. My scene is different - ...