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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75 views

Android OpenGL and non premultiplied textures

As I understand it; by default all bitmaps will will get the alpha channel premultiplied in Android if loaded using BitmapFactory. My setup: I have a 32bit bitmap(.bmp) where the alpha channel has a ...
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1answer
84 views

wglCreateContextAttribsARB is undefined

I've just downloaded the latest headers from the OpenGL registry and included them in my project. I am attempting to create an OpenGL 3+ context. Every tutorial/resource has used ...
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1answer
84 views

Errors when loading Assimp meshes

I am experiencing some oddities when loading meshes in Assimp. Some models render perfectly, while others are complete jumbles of triangles. Some Example Images: Teapot Correct - Teapot Actual ...
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52 views

Mouse click coordinates not mapping to Box2d world

I'm using Box2d in Java with OpenGL, trying to detect if a mouse has clicked on a Body. But having trouble mapping mouse coordinates to Box2d world. I have a Body positioned at 20.0f, 30.0f in the ...
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3answers
138 views

OpenGL Texture Mapping distorts image

So, I'm just trying to draw a texture to two triangles that are the same size as the viewport, but it breaks up the image and distorts it. I have tried resizing the image file and everything, but ...
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2answers
244 views

OpenGL generate hills looking vertices

I want to generate a terrain which looks like hills. Some sort of sine waves. Should be as simple as possible. But I can not figure out how. I get very scary results, which are nothing worth. I need ...
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1answer
59 views

How to fix model matrices colliding in vertex shader?

I am new to OpenGL programming and I'm writing some basic code to display a few objects onto a screen. I have a pyramid shape that I'm displaying, as well as a box shape that I am displaying. The ...
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1answer
166 views

OpenGL: I only see one square instead of a cube / giving information to vertex shader

I am new to OpenGL and tried to follow this tutorial. I use C# and OpenTK. So I translate the C++ Code from the Tutorial: My C#-Code: /* Hintergrundfarbe */ ...
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1answer
53 views

Invalid coordinates returned by glutMouseFunc()

I am using GLUT's glutMouseFunc() function to retrieve the coordinates of mouse clicks. I want to move the object on that coordinate to another coordinate. But when I click on the object the ...
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1answer
123 views

Why bother with a separate normal matrix, if there is never non-uniform scaling on the view matrix?

I am updating one of my shaders to a version of OpenGL/GLSL that doesn't automatically provide gl_NormalMatrix (for educational purposes; I'm not ripping out working code for the sake of it). ...
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20 views

Artefact in VSM as if GL_DEPTH_TEST disabled

I am trying to implement VSM and I incurred in a strange issue. I render them as follow: glUseProgram(shadowMapProgramID); glEnableVertexAttribArray(0); glBindFramebuffer(GL_FRAMEBUFFER, ...
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15 views

Transform screenquad around object's view space boundaries (GLSL)

Im not sure how to ask this, but essentially I am looking for a way to optimize rendering screen quad lights per object. I have a deferred renderer that draws directional lights onto a screen quad. ...
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85 views

How to get rid of half pixel artifacts?

I've been having a bit of trouble using OpenGL to make 2D games. I am using a traditional ortho perspective with just some sprites being rendered and moved around. It all works perfectly but there is ...
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1answer
105 views

OpenGL Question about scaling 3D Object

I got some scaled cubes (1, 2.5, 1) in a 3D Space with a grounded floor with position (0, 0, 0) and scale (100, 0, 100) like in the picture. But why are the cubes scaled out from the center. I want to ...
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2answers
149 views

How can I pass a std::vector<Vector3f> to my shader?

I have a Vector3f type which has x, y, and z properties. I have a std::vector of these vertices which describe my terrain. I would like to pass these values to a vertex shader through a uniform ...
2
votes
1answer
117 views

Shader - Transmittance or Absorption

I am trying to create a transmittance or absorption shader (glsl, hlsl, cg, etc...) in realtime but I don't find any good tutorial or white paper about this subject. I only find offline rendering ...
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1answer
333 views

How do I set a background image in OpenGL/GLFW?

I'm writing a simple 2D game with C++ and OpenGL/GLFW, and my current step is to create a menu. I finished with buttons, but I think it looks a little bit boring (with only 4 buttons and a black ...
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1answer
136 views

OpenGL - Asteroids clone - shooting bullets from spaceship [duplicate]

I am having a bit of difficulty figuring out how to shoot bullets from the front of the spaceship. I can draw it to screen, but I can't properly figure out how to create bullets each time I press the ...
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0answers
120 views

OpenGL Bump Map — Texture artifacts ?

I am learning OpenGL (and learning the math behind it) and I'm making a simple OBJ viewer, nothing fancy. I have diffuse, specular and ambient light/texture working fine and now I am implementing the ...
9
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1answer
388 views

In OpenGL, what is “zero state” rendering?

Recently at a job interview, I mentioned that I taught myself modern OpenGL and rendering with vertex buffer objects because my university only taught the fixed function pipeline with immediate mode ...
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2answers
219 views

Calculating Projectile Movement

I'm having some trouble putting together a method that will constantly move a "bullet" in the same direction accurately. Here is what I have so far public Vector3f moveFromPosition(Vector3f location, ...
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0answers
185 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 ...
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1answer
79 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 ...
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0answers
37 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. ...
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1answer
88 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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1answer
232 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, ...
3
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0answers
164 views

Variance shadow maps don't want to render properly

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 ...
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vote
0answers
69 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 ...
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0answers
38 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 ...
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vote
0answers
87 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
91 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
120 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 ...
0
votes
1answer
47 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 ...
3
votes
2answers
177 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() ...
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0answers
25 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
126 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
105 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 ...
0
votes
0answers
74 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
172 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); ...
1
vote
1answer
78 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 ...
0
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3answers
76 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
1answer
429 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 ...
2
votes
1answer
200 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; ...
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votes
3answers
141 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): ...
0
votes
1answer
216 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 ...
5
votes
1answer
110 views

Texture is black when manually building mipmap

I am trying to manually build a mipmap from a series of images. For the sake of brevity, let's assume the file containing the images I want (from 256x256 to 32x32) have paths file_1...4. What I do ...
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1answer
119 views

What is wrong with my normals?

I am trying to build a cube as a composition of many quads, with each quad being composed of two triangles. All the triangles have the same size. I am dong this (instead of drawing a single cube with ...
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0answers
97 views

Rotating a scene around a fixed axis

I am looking for a way to move my scene so that when I translate forward/back/left right it moves directly up/down/left/right on the screen. Currently it does do that until I rotate (by anything ...
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0answers
45 views

Load different grayscale images into the same texture

I have a series of images loaded as data1 = stbi_load_from_file(file1,&width,&height,&comp,1); data2 = stbi_load_from_file(file2,&width,&height,&comp,1); data3 = ...
4
votes
1answer
240 views

Do OpenGL buffers overflow to CPU memory?

This is a question about OpenGL buffers and memory. My game world is mid-sized, one contiguous space, unchanging, and only partially visible from any position. Will modern OpenGL overflow buffers ...