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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107 views

render with const depth value

This is a question that may have an answer that differs for vanilla desktop GL and GL ES 2.0 (and wishful thinking is that ES 3.0 would have the same answer as vanilla GL). What I'm doing is ...
2
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1answer
318 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(); ~...
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1answer
217 views

How can I render a JBox2D ParticleGroup?

I want to render a ParticleGroup from JBox2d using OpenGL. I've managed to define a particle group area, but I'm unsure how to draw the individual particles. Here's how I create the ParticleGroup: ...
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0answers
52 views

Why Reducing fragments by increasing geometry vertices turn out to be slow?

I am developing a ray-casting program by OpenGL. At first I made a large bounding box including the whole volume and render this box, which triggers the ray-casting. I'm trying to optimize this ...
8
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1answer
2k views

Creating a glitch effect similar to Watch Dogs

I'm currently working on a LibGDX game. When a user does something wrong, I would like all the graphics on the screen to jitter very similar to the glitch/distort effect seen in the game Watch Dogs (...
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2answers
2k views

2D games and modern OpenGL

Preconcepts Ok, so what I've gathered so far is this: don't use fixed pipeline (deprecated or going to be deprecated) vbos store "object models" (n vertex data, mostly) vaos describe how data is ...
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1answer
323 views

How can I load raw Bayer images using OpenGL?

I want to load a raw Bayer format image and convert it to RGB using OpenGL. So far I have played around with glTexImage2D() and loaded a Bayer image as a monochrome texture. My question is: how can I ...
0
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1answer
268 views

Fragment Shader output type error

StackExchange! I've been working with opengl for a bit and I'm trying to finally load the shaders instead of having them inline. I'm having a ton of issues, though. As soon as I solve one, another ...
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1answer
143 views

It possible to render a true quad (without triangles) using OpenGL?

Is it possible to render a "true" quad in OpenGL? By that I mean a square which is not made out of two triangles.
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1answer
55 views

How would I go about merging two models together in-game to create a new model? [closed]

Let's say I have two models: model 1 is hilt and model 2 is blade. How would I merge these to models together to create a sword?
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1answer
1k views

OpenGL light appears to move with camera and changes with object rotation

I have a working open gl es 2.0 3d engine (my own) that I've used in several iOS apps. I recently noticed that on a mutli-symmetrical object the lighting didn't look the same at each rotation. For ...
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1answer
1k views

model view projection multiplication order

I'm debugging a lighting problem where the camera position is effecting the diffused lighting component on my 3d model. In researching my problem I went back and am reading over all the how to ...
4
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2answers
529 views

Is there an alternative to VBOs or deprecated functions to draw many small quads?

I was thinking about how to program a user interface in a 3D game. The problem is, immediate mode (glBegin and glEnd) is deprecated for a long time but I don't think vertex buffer objects (or arrays) ...
1
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1answer
173 views

Why would OpenGL ignore GL_DEPTH_TEST setting?

I cannot figure out why some of my objects are being rendered on top of each other. I have Depth testing on. glEnable(GL_DEPTH_TEST); glDepthFunc(GL_LEQUAL); Do I need to draw by order of what is ...
0
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1answer
351 views

How can I draw a ray from the camera in world space?

How can I construct a ray from the camera position to where it looks at, in world space. My previous method is draw a line by using two points. The first point is the camera position, and the other is ...
3
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2answers
154 views

How can I draw curves above a mesh surface?

I am making an animation of a deformed sphere that represents some aspects of the wave function in a hydrogen atom. I am starting with an octahedron that i push through a tessellation shader. The ...
0
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1answer
297 views

Rotate OpenGL quad around its center

Sorry, I searched it but couldn't figure how to apply it to my code reading the other answers to similar questions. I what to rotate a quad, my code is the following: glEnable(GL_TEXTURE_2D); ...
0
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1answer
169 views

Transformations and basis vectors

I've been reading this very nice tutorial on OpenGL, and I encountered a statement which I can't wrap my head around. In Chapter 6, it states: Transformation from one space to another ultimately ...
2
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1answer
146 views

Failing to move exponential depth term to depth shader in exponential shadow mapping

I'm playing around in my little toy project to see if I can understand how exponential shadow mapping works. To begin, I have the following two fragment shaders: Light depth texture shader layout(...
2
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2answers
388 views

Render-to-texture doesn't work on nvidia cards. OpenGL 3.3

I've implemented some postprocessing effects (DOF, HDR, Bloom) into my engine. I've tested it on AMD card which supports OpenGL 4.2. Yesterday I've made a test on NVidia card which supports only ...
1
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1answer
360 views

Setting up OpenGL on Mac OS 10.10 while keeping it cross-platform

I have experience with game programming mainly in allegro or drawing everything on native windows (No graphic libraries). Now I am interested in learning OpenGL for game development. I have found ...
4
votes
1answer
505 views

How to compute point in view space from depth?

I am trying to implement do some screen space rendering but after looking over the web I still don't find answers to some doubts. First, I need to compute the point in view space from a value in the ...
1
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1answer
57 views

Do I have to use vertexArray in opengl

GLuint VertexArrayID; glGenVertexArrays(1, &VertexArrayID); glBindVertexArray(VertexArrayID); As you can see from the above code, some tutorials use this before using opengl. But a tutorial that ...
4
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1answer
1k views

C++ OpenGL ShadowMap Issue/Artifacts

I am currently implementing basic shadow mapping in my C++ Custom Engine using GLSL 4.10. It is currently working with basic PCF anti-aliasing and very minimal reduction for unwanted artifacts. Here ...
0
votes
1answer
84 views

Is this equivalent to D3DXVec3TransformNormal?

I was porting some code from DirectX to OpenGL. I have the following code: glm::mat4 rotation(1.0f); rotation = glm::rotate(rotation, degrees, m_up); m_look *= rotation; where rotation is a mat4 ...
3
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0answers
67 views

Tangents face the same direction on opposite sides of mesh

I have noticed that the tangent vectors that I am calculating are not always facing the correct direction. The tangents on the left and right of the mesh both face the same direction. Here is a ...
4
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1answer
227 views

OpenGL: Volume Heat Distortion

I'm working on adding volume effects to an existent, open-source game engine. At the moment, the engine only supports two dimensional "thruster" bitmaps with a planar heat distortion drawn over the ...
4
votes
2answers
373 views

How does a general Renderer::drawRect(0, 0, 100, 100) handle VBO's?

Lots of game engines and GUI systems have a general Renderer class with functions like: renderer.drawRect(0, 0, 100, 100); renderer.drawText(204, 452, "Hello, world!"); I understand how this could ...
0
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1answer
83 views

Reconstruct shader vertices in OpenGL

I'm not sure if 'reconstruct' is the correct term for this but essentially what I am trying to do is calculate vertex positions (that are already calculated via shader) on the CPU for the purpose of ...
0
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1answer
305 views

Calculate polygon points from image

I'm new to OpenGL, so please excuse my brevity and/or lack of technical knowledge of the subject. I need some help with rendering a polygon on an OpenGL canvas (using C# w/ Tao). I understand that I ...
10
votes
1answer
712 views

Why is it Important to have render targets with the same bit size?

I am currently thinking of what type of GBuffer I'll need for deferred shading, hence I tried also to document myself online about the most common ones and their format. Most of the GBuffer that I'...
0
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0answers
195 views

Slick2D shader crashes, but only after a while

I'm using Slick2D's ShaderProgram for shader-based drawing in my game. Some players report that after 3-10 minutes, the game inevitably crashes hard during what appears to be a setUniform4f operation ...
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1answer
552 views

How to compute matrix transform local/world on OpenGL

I'm developing an OpenGL program where each object / entity contains m_WorldPosition, m_WorldOrientation, m_WorldScale and m_WorldTransform (Vector3, Quaternion, Vector3 and Matrix4f). The problem is ...
2
votes
1answer
1k views

2D graphic over 3D perspective projection

To draw a 2D HUD (just a simple trianlge, for now) over 3D graphics in OpenGL I : draw all 3D objects, then call glDisable(GL_DEPTH_TEST) before drawing 2D HUD draw 2D triangle call glEnable(...
0
votes
1answer
210 views

Directional lights (not) rotating with camera (opposite problem)

I am trying to implement a shader for directional lights correctly, but I am bit confused as to why it works when it shouldn't and vice versa. People usually encounter problem with lights changing ...
1
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0answers
133 views

Smooth seams and banding of overlapping lights in deferred rendering

I have finally managed to get on screen multiple lights with a deferred renderer, but the result is somehow disappointing. In particular I have severe banding problem Other than having clear ...
1
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0answers
182 views

Why is my diffuse lighting changing with camera position?

I am trying to do lighting in view space, but I am afraid I have an issue. I calculate the normals as: N = norm_mat * vec4(vert_norm,0.0) where norm_mat is the transpose(inverse(model_view_mat)). ...
1
vote
1answer
947 views

Problem setting up OpenGL dev environment in Ubuntu 14.04

Currently I'm using this tutorial to get started with opengl.So when I try to compile the example program : #include <GLFW/glfw3.h> #include <thread> int main() { glfwInit(); std:...
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0answers
149 views

How do I fill a shape with a texture in Libgdx?

I am making a 2D racing game. I want to fill the area of the ground object with a texture. I have the shapes of the ground (a Box2D shape). If I make images of the ground with textures, it uses a lot ...
5
votes
1answer
874 views

physically based shading, how to combine specular & diffuse parts?

After writing 'standard' phong & blinn shaders for a while, I recently started to dabble in physically based shading. A resource that helped me a lot are these course notes, especially this paper -...
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votes
2answers
188 views

OpenGL Depth Test Errors [closed]

I've been working on this problem for a while now. My problem is that the sphere in the top image, is under-lapping the plane which should have a lower Z value. Although, when depth testing is ...
0
votes
1answer
98 views

Can diffuse and specular component of Phong model shine thru object?

I have been implementing simple 3D engine in OpenGL, mostly based on tutorials by Tom Dalling. I have implemented the Phong lightening model as described in his tutorial, but I see light artifacts on ...
0
votes
2answers
70 views

Overload how an object instance of a class is treated when used

So I've made this struct that encapsulates a glm::vec4. This is because vec3s are treated as 16-byte in GLSL, but I don't want to assign a vec4 if I only really need 3 components. Anyway, my question ...
0
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1answer
63 views

Player being covered by glClearColor?

Here is a video of the problem: https://www.youtube.com/watch?v=6vnDOB1Vk4o (this is the game I've been making for fun/practice). You notice, in the beginning of the video, I walk off the map and ...
0
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0answers
200 views

Artifacts rendering high-poly procedural meshes with OpenGL

I am having some issues when rendering some procedural generated meshes. There are some really wierd artifacts when rendering high-poly count meshes (not that much actualy). I have been able to ...
2
votes
2answers
979 views

Opengl Quad Tessellation Control Shader

I have the generic tessellation evaluation shader for triangles but I need to make it work for quads. Is there any chance someone could explain what is happening here and point me in the right ...
2
votes
1answer
477 views

How to improve Batch Rendering to work with 3D skeletal animation data

I've implemented a batch rendering technique that is described in detail here: http://www.gamedev.net/page/resources/_/technical/opengl/opengl-batch-rendering-r3900 I'd like to extend it now to ...
3
votes
1answer
554 views

I want to render some surfaces in GLSL with normal maps, and some without

I have normal mapping working in my game, but I want to only use normal mapping for some surfaces, and not others. Right now, as far as I can tell, my shader is applying an incorrect normal of (0, 0, ...
2
votes
1answer
284 views

How can I implement a camera like the one in RotMG?

RotMG, an MMO top-down shooter, takes on a unique 2d-3d style, and has an intriguing camera; The game is obviously 3d, not simply isometric, and if you play the game and turn on camera rotation you ...
1
vote
1answer
839 views

Triangles go missing as Z changes

I'm rendering a height map using shader-based OpenGL (3.3 to be precise). The height map data is from a grayscale bitmap (2D array of bytes). The dimension of the bitmap is 256 x 256. With this data, ...