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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1answer
52 views

OpenGL ES 2.0 facet lighting

I am trying to figure out if there is a way to achieve facet lighting in OpenGL ES 2.0 without extensions. I know it is possible if I don't used indexed vertices but I don't really want to do that ...
5
votes
1answer
356 views

Calculated normals for mesh not working

I am trying to implement a 3D mesh viewer with C++ and OpenGL ES 2. I am currently struggling with the calculation of the normals for the vertices, or at least I think that is where the problem ...
1
vote
0answers
52 views

blending with OpenGL glBlendFunc and glBlendEquation

I want to draw a bunch of images in front of a background. Where images overlap, I want those to be blended together (for now, using a mix of 0.5 source * 0.5 destination color every time an image ...
2
votes
0answers
165 views

OpenGL Render Queue Design

I am currently designing the rendering system for a 2D game built in C++ and OpenGL, and am unsure about how to go about implementing a sorting procedure to maximise efficiency and minimize OpenGL ...
-1
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1answer
45 views

FRAMEBUFFER_UNSUPORTED (0x8cdd)

I've tried to implement bloom following this tutorial. But everytime I get the framebuffer object error 0x8cdd, which I believe means FRAMEBUFFER_UNSUPORTED. I'm pretty sure the problem occures ...
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0answers
108 views

Why is my OpenGL 4.1 shader not working on OS X Macbook ( works on Linux )?

I've recently rebuild shaders for my program and it stopped "working" ( black screen ) on OS X ( El Capitan ), but it's ok on Linux. What could be the cause? There are no shader compilation errors, ...
0
votes
2answers
126 views

Why does rotating my quad appear to move it farther away?

I have created a 3x3 matrix class which is then passed over to OpenGL Vertex Shader for transform my Quad. I have been trying to rotate my Quad around Z-Axis. Rotation is working but the Quad getting ...
0
votes
1answer
49 views

OpenGL: strange thing with depth and text rendering

TL;DR I render a scene with M,V,P matrices as always. Than I render something (in this case - text) without any matrices and using separate shaders pair on coordinates with Z = -1. Somehow it's ...
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0answers
62 views

Unity - _LightMatrix0 and Directional Light

I am trying to access the _LightMatrix0 in a forward base pass to calculate some light point of view coordinate but it seems that the _LightMatrix0 is empty with directional light. Any idea how can I ...
1
vote
1answer
77 views

Strange artifacts when using gl_FragCoord to access texels

I ran into a problem with using gl_FragCoord variable to access texels. The problem can be illustrated by following example: First I render a textured quad into texture of size (W, H) where W and H ...
5
votes
3answers
227 views

Painter algorithm vs. 3D rendering with Z-buffer when drawing 2D Sprites

I'm currently developing a tile base engine. I want it to look like your average old school tilebased RPG like Zelda - Link to the past (orthographic projection, squared tile texture, textures ...
0
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0answers
32 views

Shader - Directional Lights Depth

Is there a way to retrieve the deph from directional lights ? I can access the _ShadowMapTexture but this is not the depth. I found how to access the shadow map of, I think, every light type by using ...
0
votes
2answers
44 views

Cannot get mask with multiple textures to work

I am trying to render three textures: Background, Black/White Foreground Mask and Foreground. I have used this OpenGL - mask with multiple textures, but I cannot get it to work. I only get the last ...
0
votes
1answer
47 views

m_BoneMapping is undefined in OpenGL Step By Step Skeletal Animation Tutorial [closed]

I am new to this website I was following this specific tutorial on skeletal animation and I have a good idea on what it is, but when I was following his implementation he used a variable called ...
0
votes
1answer
48 views

Unity - Access to svPosition in fragment shader

I am trying to access to the svPosition in my fragment program in Unity but I keep having this error. invalid input semantic 'POSITION': Legal indices are in [1,15] invalid ps_3_0 input semantic ...
1
vote
1answer
26 views

Vertice combination code crashes when “large” amounts of vertices are introduced

I have a 2D tile rendering system. In my tile storage class, I have a two dimensional array of Tiles, and a build method which combines all of the vertices of the tiles which are not equal to ...
2
votes
0answers
87 views

Subsurface Scattering - Transmittance

I have a question related to SSS and especially transmittance. I've looked at several papers about that topic, most of them from Jorge Jimenez, which are very interesting and, I admit, a bit hard for ...
1
vote
1answer
83 views

Little question about glPolygonOffset

q1. After passing stencil test, depth test, etc. what version of "depth" of fragments after primitive rasterisation will be written to depth buffer? With shifted values or without? (Due to ...
0
votes
0answers
26 views

How to screen color blend spritebatch?

batch.setBlendFunction(GL20.GL_SRC_ALPHA, GL20.GL_ONE_MINUS_SRC_ALPHA); batch.setColor(new Color(0xFF0000FF)); batch.draw(...); Expected result: Current result: How can I achieve something ...
2
votes
1answer
65 views

Cannot connecting texture to heightmap using mapped uniform location

In my shader program, I have my attributes and uniforms added to a map for each. What I have displayed is a heightmap, but cant seem to connect the graphic texture to display. mUniformList ...
0
votes
1answer
44 views

Using one GLSL shader program for textured and untextured rendering?

Rather than have two separate shaders in my OpenGL code (one for when a texture is bound, one for when none is bound) I usually go for one shader program which handles both. This is my usual fragment ...
1
vote
0answers
187 views

How to use OpenTK (OpenGL) with MonoGame?

So I've been making a snake game using MonoGame (DirectX Only). I added movement, controls, feeding and growing in length. I wanted to add smooth animations to the game because the snake is just made ...
6
votes
2answers
377 views

Know if you're fully utilizing the GPU

I render ~17.000 VAOs each frame. 2.840.386 triangles. Only applying texture, nothing else. I have three computers and the performance across them is not as expected. Cheap laptop(i3-4010U & ...
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votes
1answer
115 views

How to pitch, yaw, roll, an object like a flight simulator in OpenGL?

I'm working on a college Graphics project using LWJGL (OpenGL in Java). I've done most of the scene but I got a problem in figuring out the jet's orientation. Here's how I tried it at the very ...
1
vote
1answer
127 views

OpenGL/SDL2 How to resize the render area with the window?

After calling SDL_SetWindowSize, the area being rendered to doesn't change with the window, so if the window gets bigger, it leaves a black area on the top and right sides. I am adjusting the OpenGL ...
0
votes
1answer
58 views

My point light shadows only really work if my point light is at the world origin (0,0,0)

When I move the light, the shadows will fall apart as if their occluders aren't occluding them in certain areas. For example, in the following scene, I move a pointlight 400 units down the Z axis, I ...
0
votes
1answer
36 views

OpenGL Face Order

i have written a simple OBJ-file loader to render meshes using OpenGL. But there is a problem displaying the loaded mesh. It seems that faces that from the background (far) are displayed above the ...
0
votes
2answers
67 views

Text in game with not english alphabet

I need to render some special text in my game. Currently I can render any text that use classic letters of english alphabet, but I have some problems with special alphabets. How do I render text: I ...
0
votes
0answers
47 views

Any call to framebuffer methods causes crash. (MinGW)

For a long time, I have been using LWJGL. This library is pure awesomeness, however I was looking into learning the lower level API that was used in C++. I am new to the idea of pointers and other ...
2
votes
1answer
55 views

Polygon edges visible when using per-fragment lighting (OpenGL)

I have created a mesh in Blender (just a sphere with a texture over it; it's supposed to look like mars) and I've exported it as OBJ. I've tried it both with exporting with normals in Blender's export ...
0
votes
1answer
218 views

OpenGL shows a black screen

I am new at OpenGL, I try this example: http://stackoverflow.com/a/31524956/4564882 but I get only a black widget. The code is exactly the same. this is the code associated to the QopenGLWidget: ...
3
votes
1answer
149 views

How do 2D volumetric lights work?

Context So in my current project (written in Java using LWJGL / OpenGL, so GLSL for shaders) I added lighting quite a few months ago, which was already an interesting challenge, having never done ...
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vote
0answers
53 views

Implementing Separating Axis Theorem in 3D with C++/OpenGL

Using an Octree data structure provided to me by an acquaintance that gives min/max bounding box values, I've been able to write an algorithm that takes the global centre points, face normals and half ...
2
votes
0answers
27 views

GL.Scissor not working as expected

I have some code for rendering a button in an application and I want to clip the text if it's wider than the button itself. Here a bit of code to describe what I'm doing: ...
3
votes
1answer
70 views

How to store renderer vertex / index data in scene graph objects?

I have a SceneNode class which contains a Mesh instance. The Mesh class stores client side information such as vertex and index arrays (before they're uploaded to the GPU). I also have an abstracted ...
0
votes
0answers
17 views

Implement steamworks_sdk in OS X

Well, I'm using OS X and using as compiler 'g++' and well editing in VIM. I wan't to use the steamworks_sdk. I can use the all the code that is in 'sdk/public/steam' and well, compile all. But I ...
0
votes
1answer
148 views

Java - LWJGL OBJ Loader with Materials not rendering

So I successfully loading my obj file but I obviously want to get materials on it. I added the vt(texture) to the OBJLoader and the Model.render but still rendering textureless. I have exported the ...
1
vote
1answer
51 views

Terminology for the way Transformation Matrix Data is treated

I recently asked a question at math stack exchange and realize a similar questions is more suited for this forum, but the original is here: ...
1
vote
2answers
54 views

c++ Opengl handle elements drawn

I am currently working on a game and I want to know if there is any way of handling with the elements i am drawing . For example : if i draw in a loop 100 cubes , how can i show / hide the cube number ...
4
votes
1answer
182 views

Rotate billboard towards camera

I'm trying to create a particle system in OpenGL, and as such I need to use billboards. I need these billboards to face the camera at all times. The tutorials I've been following only rotated the ...
3
votes
1answer
72 views

How to determine what color will be written into single pixel framebuffer?

I thinking about rendering into single pixel (1x1) framebuffer. For example we have two triangles which covers whole NDC area, one is green second red. What color will be written to 1x1 framebuffer? ...
6
votes
1answer
200 views

How can I extrude a regular, grid-based 2D shape to 3D?

I have a list of vertex coordinates which encircle several 2D areas. Orthogonal lines only, but not necessarily convex areas... similar to PCB traces of conductive copper areas. I want to draw them ...
4
votes
1answer
65 views

What is the fastest way of drawing simple, textured geomtries and keeping the depth test?

I'm looking for a fast way to draw simple 3D geometries - that will consist of up to 10 vertices. Each of them will have a texture (though varying between geometries). I also want to store the ...
1
vote
0answers
50 views

OpenTK crashes with Mono

I've implemented OpenTK as a secondary renderer which would let me support Mac/Linux only to realize that for some reason, even without any modifications (new MonoGame project), the application would ...
3
votes
1answer
130 views

VBO rendering crashed with glDrawArrays

I'm playing around in LWJGL3 and I'm experiencing an issue regarding glDrawArrays. At glDrawArrays the JVM crashes. I'm using modern OpenGL and therefore I have my own shaders and matrix ...
1
vote
1answer
90 views

OpenGL Picking: How to avoid entities?

I have a terrain and entities(npc, house...). I'm able to convert screen coordinates to world coordinates with the glReadPixels function: glReadPixels(mousePosition.x, mousePosition.y, 1, 1, ...
1
vote
0answers
75 views

Point Light shows black box & rect (PointLight not working) - libgdx 3D

I am creating a 3d scene currently a box and rect, and trying to enable lighting. When i create a PointLight and add it to Environment everything turns to black color? all i want to do is ...
4
votes
0answers
75 views

Draw Edges in OpenGL

I use blender game engine, and blender use openGL for graphics. How can I draw lines around all 3D objects? Would this be a job for a filter? Mainly, I want my end result to look drawn. I found this: ...
3
votes
0answers
39 views

When I add in Java transformationMatrix I can't see images? [closed]

When I add in Java transformationMatrix I can't see images moving but when I remove it I can see why and how to fix it? Any ideas how to fix it? My Renderer class: public class Renderer { ...
0
votes
2answers
83 views

Inverse of perspective matrix, for what?

I dont understand for what i need the inverse of the perspective Matrix in Computer Graphics and how do i calculate it?Maybe someone has an explanation for me.