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
74 views

Reading mesh data back from OpenGL vs storing two copies

I'm wondering if whether it's a good idea or not to keep a copy of vertex data in the main memory or just read it back via glGetBufferSubData (or glMapBuffer/glMapBufferRange). The reason why I'd do ...
4
votes
1answer
81 views

Water effect using DuDv Map weird look

I'm trying to apply a DuDv Map effect (distortions) on my water. My texture is 512x512 in size. I'm using the following code: (Vertex Shader) out vec2 texCoord0; void main()... { texCoord0 = ...
2
votes
1answer
47 views

OpenGL pitching problem

I've been trying to implement several camera movements for my application. So far yawing, rolling, strafing, walking has been working properly, but I can't get my pitching to work properly. If I ...
1
vote
1answer
53 views

why doesnt this function work? glsl opengl c++

Im trying to move a transformation matrix onto the gpu, and I managed to find this code to help me on the way: vertex.shader: #version 410 core layout ( location = 0 ) in vec3 vertex_position ; ...
1
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2answers
167 views

Optimize drawing “different” sprites in OpenGL ES 2.0 (batching?)

I started experimenting with OpenGL ES 2.0, and I'm trying to figure out a way to optimize/batch sprite drawing, where sprites only have the texture in common, but differ in the following properties: ...
1
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1answer
96 views

Why am I getting these artifacts when rendering polygons with OpenGL and SDL from far distance?

I'm working in a toy BSP (quake3 version) renderer. I started creating the context and handling the input with GLFW but then I switched over SDL. The performance change was amazing with SDL leading ...
6
votes
1answer
262 views

Why do I see spaces between polygons in OpenGL, only on an Nvidia 720M?

I'm developing an OpenGL application that renders .obj 3D models. I use VBOs to render the polygons. Using the same code, the loaded models appear fine on all PCs, except on my Nvidia 720M. My ...
0
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1answer
124 views

Help me understand this vbo/rotation, and how its done opengl c++

Im pretty new to opengl, and I just cant figure out how to rotate this vbo/vao in 2d space. This is how I bind my coordinates: float points[] = { 0.0f, 0.10f, 0.0f, -0.10f, -0.10f, 0.0f, ...
2
votes
1answer
102 views

How can I recover polygons and normal maps from compiled games through emulation of D3D or OpenGL?

I am trying to generate labeled training data for an artificial visual cortex to learn on. I'm looking for a tool that will, instead of rendering the scene at each pixel just give me the pre-rendered ...
3
votes
1answer
50 views

How to hide a post-processed mesh outline when/where the mesh is hidden

I'm working on setting up an active outline in my 3d engine, a highlight effect for selected 3d characters or scenery in the screen. After working with the stencil buffer and getting some ...
0
votes
1answer
28 views

OpenGL 3.3+ bounding volume only partly drawn

I am currently trying to set up a little debug view as I am planning to implement occlusion queries later. For those, I have written code to determine the "extreme coordinates" of the VAO I want to ...
15
votes
1answer
2k views

Phong lighting - there is something very strange with specular lighting

I implemented Phong lighting. Everything seems to work - torus and spheres are lighted as expected, etc. But I notices something strange regarding specular lighting of directional light. Here are two ...
0
votes
0answers
82 views

OpenGL: Making a Cube Class with Interleaved Color Data?

So, I am trying to make a basic "Drawable" class that handles a lot of the drawing for me in the background and I want to use modern OpenGL (no begin and end statements). I keep just getting a blank ...
0
votes
0answers
36 views

Invalid GLSL on some machines

I'm writing a game engine using OpenGL 4.3 using gcc 5, mainly to teach myself graphics programming. Initial development was on my Surface Pro 3 using mingw-w64 and worked like a charm. I've decided ...
2
votes
1answer
51 views

Check if .dds texture is gamma-corrected

How can I check if .dds texture is gamma-corrected? It seems to be gamma-corrected since after manual gamma correction in fragment shader image is too bright. But I wanted to be sure.
0
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0answers
26 views

How to map opengl 'canvas' to resolution

I am playing gomobile - framework that allows to generate mobile applications in go language. It uses opengl to draw on screen. This is first time I get involved with opengl. In my mobile device, I ...
1
vote
1answer
100 views

How to not render what is behind object?

I am working on a 3d project using openGL. I am looking for a way to optimize my renderings. Is there a way to tell if an object is behind another object and thus not visible to not waste time ...
2
votes
1answer
113 views

How to attach a framebuffer to a whole cube map from a GL_TEXTURE_CUBE_MAP_ARRAY?

I'm trying to make shadow cube maps in an array. I want to draw each shadow map with a single pass using a geometry shader, which I read about here: ...
7
votes
1answer
157 views

What is the optimal texture size?

I recently added a texture packager to my project that will pack a certain amount of textures into a single one, like this: So for example this one is 582x1023 pixels in size. The goal of adding ...
0
votes
1answer
45 views

OpenGL: Objects wont draw at certain angles while using lighting(shaders)

I was following this tutorial (http://www.lighthouse3d.com/tutorials/glsl-12-tutorial/point-light-per-pixel/) but when the camera is at a certain angle, if I had alpha test and blend enabled the cube ...
1
vote
1answer
55 views

My Sprite is disappearing when it collides with my floor (libGDX)

I am just starting to build the game "engine" and I am using a sprite drawn in the same position as a rectangle and the two always move together. I have another rectangle which is the floor when the ...
1
vote
1answer
91 views

What does glTranslatef function is translating in this code?

I understand translation from mathematics view where we can have a triangle with a certain coordinates. We can translate this triangle by multiplying the coordinates of the triangle (expressed in the ...
1
vote
1answer
68 views

Assimp, Blender and model rotating

There is something I can't figure out. I have two models - grass.blend and tower.blend. grass.blend: tower.blend: Note X, Y and Z axises. The problem is that when I load these models using ...
1
vote
2answers
58 views

SDL_LoadBMP into glTexImage2D results in scewed colors

I read up on this but i can not find the error. Some suggest switching the format from RBA to RGBA but the surface data says it is 3 byte data. Here are snippets and results of my source. Loading ...
1
vote
2answers
113 views

OpenGL 3.3 tilemap rendering techniques?

I'm trying to draw regular 2D tiles to the screen from a single texture but there are a few ways to accomplish this and I don't feel like I know enough about rendering to assess the trade-offs ...
1
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1answer
52 views

View Matrix to Texture Matrix

I'm converting view coordinates to texture coordinates for both my shadow maps and Screen space reflections. I keep seeing this conversion in examples: var T = new Matrix { ...
0
votes
1answer
80 views

OpenGL, Blender and model optimization

I'm learning OpenGL and there is something I don't understand regarding model loading. Lets say I found a free .blend model of a tree. The problem is - currently in my program all models have only ...
4
votes
1answer
66 views

Only one object rendered to FBO for Shadow Map

I've been playing around with rendering shadow maps using FBOs in OpenGL. I set up a simple directional light in my engine and managed to get a shadow map rendered. My Scene is a big castle and the ...
1
vote
1answer
92 views

Smooth matrix rotation

I have a coded a simple example for a matrix rotation. The example rotates a sphere around its center. The problem is that the rotation is not running perfectly smooth and I'm wondering why. Here is ...
1
vote
1answer
126 views

FAST position reconstruction from depth

I'm struggling a lot with reconstructing the world space position (or alternatively the view space position) from depth (by reading the depth buffer) in a performant way (in a full-screen ...
1
vote
0answers
68 views

Libgdx - Transparent color over texture

I am attempting to tint a texture a color but I want the texture to show under the tint. For example, I have a picture of a person but I want to tint them a light green and not change the transparency ...
2
votes
0answers
102 views

Shadow mapping - Can't get the right texture coordinates

I'm trying to implement shadow maps for Spotlight's, but alas I can't get them to work. I have verified that my fragment shader is getting the shadow map texture. I can sample from it in the ...
0
votes
2answers
52 views

Shader value remap - Blend Falloff

I would like to know if there's a way to remap a value that goes from 0 to 1 constantly like this. Into those values (those are examples). This might be some function transformation but I can't ...
2
votes
1answer
66 views

OpenGL vertex data per index

Usually, vertex data is assigned to a particular vertex, like this: [data] [vertices] [1.31] -> [1, 13, 5] [84.3] -> [5, 8, 12] [.095] -> [8, 3, 10] Then, you would typically have an ...
9
votes
4answers
535 views

How to load a spherical planet and its regions?

I'm designing a game partially composed of planets exploration. I want to use pseudo-random generation for them, regenerating from a defined seed when I have to load them rather than store every ...
-2
votes
2answers
177 views

Is a bitmap fast enough for a 3d game?

I would like to learn how to create some 3d games from scratch, but i need to know what the fastest way to create a frame would be. Would it be converting an array of pixels into a bitmap, or is there ...
1
vote
0answers
53 views

Converting glsl shaders

I need to convert these shaders from #version 400 core to #version 130 successfully but for some reason when I do it my models are not rendering properly when I load more then one type and I cant find ...
0
votes
1answer
30 views

OpenGL Mapped Memory Shader Source

Is there any way to get a pointer to a newly created shader object's source? I'd like to load a shader directly from file in to my shader object instead of loading to an intermediary variable and then ...
3
votes
1answer
157 views

deferred tiled lighting

EDIT I have discovered that it does not seem to be the lighting calculation but the culling code because when i draw the lights without the culling it works perfectly. I have been attempting to ...
2
votes
1answer
93 views

Tiled deferred rendering light culling

I'm trying to implement tile based light culling in opengl using a compute shader. I am using this as a guide. The lighting calculations work fine but the point light culling doesn't seem to work any ...
3
votes
2answers
202 views

How to achieve a dynamic soft see-through hole effect in a wall with shaders?

I'm looking for a way to create a dynamic soft see-through hole effect for room walls. I know a few ways how to do it (for example multitexturing with second layer being the hole mask in screenspace), ...
1
vote
1answer
46 views

3D mesh culling issue, further faces showing through closer faces

I'm trying to render a generated mesh using libGDX which acts as a java wrapper for openGL. The issue i'm having can be seen in the screenshot below. The faces of the mesh that should be hidden by ...
0
votes
0answers
44 views

Offscreen frame buffer lwjgl

I want to create simple 2d lighting. So my idea is to render everything on the default buffer and then apply light mask. For the light mask i want to use frame buffer which later i will apply on the ...
0
votes
0answers
65 views

Color bleed ZX Speccy style

When having fun writing an imitation shader of attribute clashing on the ZX Speccy in OpenGL 3 and some fancy shaders, but I can't seem to think of an eficcient way for creating the attribute block ...
1
vote
1answer
122 views

OpenGL 3.3+ Problem with ortho projection for UI/HUD

I have to a little bit of a problem with drawing HUD elements on top of my 3d world using a ortho projection. My 3D world keep getting render but there is nothing showing of my UI. I wrap the code ...
0
votes
1answer
116 views

OpenGL One Color Per VBO

Recently I have been working with OpenGL and have decided to use colors instead of textures. However, since the project I am working on is going to have a low-poly look, I want each color to stand ...
0
votes
1answer
46 views

Issue creating a dynamic seemless cube map

I have a function for building a cube map, given a location in space. I also have a system for displaying cubemaps (either loaded from images or given as a texture handle), and they work fine and are ...
0
votes
0answers
27 views

Pass custom data rather than vertices/indices to GPU?

(For reference, I'm using OpenGL 3.3, core profile.) I'm attempting to render a decent number of 2D quads on the screen. Each quad is different, and a GLSL shader does all of the work of rendering ...
7
votes
1answer
534 views

How to render portals in OpenGL?

I am making RPG in OpenGl and I need to make some portals. How should I render it if I want to see through the portal on the other side?
1
vote
1answer
64 views

How do I store an FBO'S as a cube map?

As of late I've been trying to implement Cubemaps in my engine, and have managed to get the rendering side of them working. Currently, I'm trying to implement a function for creating them, but I ...