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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2answers
146 views

Combine flat and smooth shading with a single model geometry

I need to be able to switch between smooth and flat shading interactively. Is there a way to do this efficiently with a single geometry? For example, smooth shading does not require duplicate ...
0
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0answers
71 views

Tessellation shader pass-through : Nothing displayed

I am trying to set a pass-through tessellation shader and then build on top of that while learning. From what I found/read I need to do in the TE shader everything that was done in the vertex shader ...
1
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0answers
43 views

Sprite framework binding multiple textures

In an attempt to batch render as many quads (sprites) as possible, I'm instance rendering a single unit-sized quad and passing in a buffer of per-instance data that includes width/height, texture ...
1
vote
1answer
112 views

For Vertex Buffer Steaming, Multiple glBufferSubData VS Orphaning?

I was learning OpenGL recently. In games, we need to update the position of game objects frequently, and they will come in & out of screen constantly. So it means in rendering we need to update ...
0
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1answer
88 views

Backface culling without light leaking through

I want to be able to see through walls, so to do this I used planes for the walls, and enabled backface culling. However with shadow mapping I have a lot of light leaking through: I read that using ...
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0answers
48 views

Jmonkey Translucent Render Bucket fails to model object last

So I have a weapon model that moves wherever the camera moves and the rotation of the weapon is the same as the rotation of the camera. Additionally I added the weapon to the Translucency Queue Bucket ...
0
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1answer
104 views

OpenGL not rendering full scene, it is a mystery [closed]

I am trying to draw a scene in the sort of style of mock vector graphics. I've helped on a 2D game before with GLSL, but I tried to keep a simple approach to this project since I'm working by myself, ...
-1
votes
2answers
68 views

Loading texture in opengl without using shaders [closed]

Thanks in advance for answering this . I am using SOIL to load an image through opengl . Below is the description of my code and the image that it is loading is weird . typedef struct { ...
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votes
1answer
87 views

Uniform Block solve padding/alignment for vec3 in CPU struct

I have a struct on the CPU which I'm sending to a uniform block in my shader. After a bit frustration I finally got it to work. The problem I had was that vec3s are actually treated as 16-bytes, or in ...
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0answers
56 views

How can I get the position of a cursor on world space on a 2D game

I am trying to make simple 2D top down shooter to train my skills on Graphics programming and I am having trouble getting the input. I am using glm as my math library, what I am trying to do on the ...
0
votes
2answers
134 views

How can I efficiently render lots of 2D quads?

I have lots of 2D quads. I write their local vertex position info to a buffer (accompanied with a world transform matrix) which gets sent to the render thread. I then pass the world transform matrix ...
0
votes
1answer
96 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 ...
0
votes
1answer
118 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 ...
1
vote
1answer
109 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 ...
1
vote
0answers
57 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 ...
0
votes
3answers
150 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 ...
1
vote
2answers
275 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 ...
1
vote
1answer
62 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 ...
0
votes
1answer
171 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 */ ...
0
votes
1answer
63 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 ...
5
votes
1answer
133 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). ...
0
votes
0answers
22 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, ...
0
votes
0answers
20 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. ...
0
votes
0answers
88 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 ...
0
votes
1answer
117 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 ...
1
vote
2answers
163 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
124 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 ...
0
votes
1answer
366 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 ...
0
votes
1answer
139 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 ...
1
vote
0answers
125 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
votes
1answer
398 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 ...
0
votes
3answers
313 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, ...
0
votes
0answers
214 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
102 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 ...
0
votes
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. ...
0
votes
1answer
95 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 ...
1
vote
1answer
321 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
votes
1answer
190 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 ...
1
vote
0answers
74 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 ...
0
votes
0answers
39 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 ...
1
vote
0answers
105 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
99 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
125 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
49 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
181 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() ...
0
votes
0answers
26 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
156 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
110 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
83 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
186 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); ...