0
votes
1answer
98 views

Orthographic Projection Issue

I have a problem with my Ortho Matrix. The engine uses the perspective projection fine but for some reason the Ortho matrix is messed up. (See screenshots below). Can anyone understand what is ...
1
vote
1answer
71 views

Does scaling affect performance in OpenGL? [closed]

I've never been able to understand the best practice in this context. I usually want to ship my game with as minimum size as possible. So whereever possible, I try to use scaling of my graphics. Let's ...
0
votes
0answers
72 views

OpenGL shading doesn't work with different projection and view matrices?

I found an online (public-domain) code to do marching cubes, and I am trying to adapt this code to work in my own project. The code uses GLUT and "older-style" OpenGL, whereas I am using GLM and ...
12
votes
4answers
1k views

How can I use the graphics pipeline to render volumetric data based on a density function?

Both graphics APIs (OpenGL and DirectX) devise a well defined pipeline in which several stages are programmable. These programmable stages require to take a fixed minimum amount of data and are ...
1
vote
3answers
103 views

Technique suggestion to render corroded pipes in 3D

We currently have a lot of data relating to cracks/corrosion/deformations in metal pipes which at present, can be viewed in a crude flat/2D application which makes the metal anomalies hard to spot. ...
1
vote
2answers
180 views

How are red dot/reflex/holographic sights implemented?

In first-person-shooters like Call of Duty, the hologram only appears when it is behind the glass portion of the sight. In OpenGL, would it be implemented by rendering the glass to the stencil buffer ...
2
votes
1answer
177 views

OpenGL - have object follow mouse

I want to have an object follow around my mouse on the screen in OpenGL. (I am also using GLEW, GLFW, and GLM). The best idea I've come up with is: Get the coordinates within the window with ...
1
vote
1answer
107 views

Are there any reasons to use Legacy (2.X) OpenGL?

The benefits are well documented of the Modern OpenGL 3.X & 4.X API's, but I'm wondering if there are ANY benefits to keeping with the old OpenGL, Or if learning OpenGL 2.X is a complete waste of ...
0
votes
1answer
106 views

What is wrong with my specular phong shading

I'm sorry if this should be placed on stackoverflow instead however seeing as this is graphics related I was hoping you guys could help me: I'm attempting to write a phong shader and currently working ...
2
votes
1answer
162 views

draw fog of war using shaders

I am making a RTS game, and I'd like some advice on how to best render fog of wars, given what I'm already doing. You can imagine this game as being a classic RTS like Age of Empires 2, where the fog ...
2
votes
4answers
235 views

OpenGL setup on Windows

I have been trying to use OpenGL for two days now. First on Mac, then on Windows. The problem with Mac is that it doesn't support the newer versions of OpenGL. I ran a tutorial that actually did get ...
0
votes
1answer
72 views

OpenGL ES 1 Pixel Error?

I am developing a game on android using OpenGL ES 1.0 for Android OS. It is a 2d game using a simple Orthographic projection and textures for the sprites. One of these textures has a small line (it ...
0
votes
1answer
87 views

WebGL wrong scaling of rectangle

I'm working with this tutorial http://www.html5rocks.com/en/tutorials/webgl/webgl_transforms/ and my result is, that the rectangle moves in the direction of it's scaling values, and also scales at ...
0
votes
0answers
33 views

Keeping relative size with different resolution

I'm making a GUI system and want the components having a konstant relative size, even if I'm changing the resolution. Since I'm using the relative OpenGL coordinates to place them, there is no ...
0
votes
2answers
182 views

Do Java and Actionscript use OpenGL?

As far as I know there are only 3 base graphics libraries on Windows, the GDI, OpenGL and DirectX, is that correct, so that means that Java, Actionscript and all language use one of these 3 libraries ...
0
votes
2answers
66 views

Clamping large content to smaller area

I'm using OpenGL (with LWJGL) in Java, but the question is language independent. I have some region (a rectangle for simplicity), and, let's say, a big tiled map which I want to show in this area. ...
1
vote
1answer
92 views

DirectX Bullet Tracer Effect

I'm wondering if anyone knows some common and efficient ways to do a fast tracer for an instant bullet. I've seen people speak on forums of using primitive lines with DirectX, but I doubt this ...
3
votes
2answers
226 views

Is there any reason why there isn't a cross-platform implementation of DirectX?

Similar to how Mono can compile C# to various platforms, why isn't there an API that conforms to DirectX's specifications but can produce binaries for all platforms? I understand that there is OpenGL ...
0
votes
0answers
115 views

Calculate parameters for orthographic matrix for directional shadow mapping

I am struggling with how I can fit my scene in an orthographic projection, based on what is visible by the camera. All tutorials so far explain almost everything in perfect detail, and then for the ...
0
votes
0answers
82 views

Shadow Mapping: How to calculate Axis Aligned Bounding Box?

I am trying to implement Shadow Mapping, which is actually working with an AABB that always covers my entire scene, but (obviously) it gives very blocky graphics. So I figured I need to calculate a ...
0
votes
0answers
30 views

Rotating an object towards a point in OpenGL C++ [duplicate]

I calculate the matrix like this: modelMatrix = glm::translate<float>(position) * glm::rotate<float>(orientation.x, glm::vec3(1, 0, 0)) * glm::rotate<float>(orientation.y, ...
1
vote
1answer
139 views

How to enable geometry shader in OpenGL 4.2?

I'm porting my Direct3D-based engine to OpenGL and I'm using geometry shaders for rendering text characters (basically, textured billboards). D3D version works fine, but in OpenGL mode it gives only ...
1
vote
3answers
312 views

How do I efficiently use 16 bit texture coordinates?

While loading a model I get a big array of 32 bit floating point texture coordinates. I just upload that to a single vertex buffer (along with other data, such as vertices, normals, etc.) and use it ...
3
votes
1answer
279 views

Solving banding with additive blended particles

I needed to implement particles for my 2D game, written in C++ with OpenGL for graphics, so I went ahead and created a nice geometry container to batch particles together and then implemented the ...
0
votes
1answer
33 views

Versions of GL and its device that don't display or required powers of 2 for the sprites

From this question aside from identifying possibilities of displaying images that don't needed to require powers of 2, what are the versions of GL that can actually display images even if don't needed ...
3
votes
2answers
331 views

When is the Z coordinate normalized in GLSL?

I thought that whenever you transform an object to world space, then view space and finally screen space, the last matrix you apply(the projection matrix) normalizes the z values between 0 and 1. ...
2
votes
1answer
267 views

How does the fragment shader get data from the vertex shader?

How can any interactions between these two shaders work? I mean the vertex shader sends a vertex's color to the fragment shader, but that's only one fragment, what about all the other ones between the ...
1
vote
1answer
256 views

What is the difference between shader uniforms and attributes in OpenGL?

I don't fully understand the differences between uniforms and attributes. To be honest, I probably haven't even used attributes. Can uniforms change for each vertex? I mean to calculate the vertex's ...
2
votes
1answer
172 views

Are ambient, diffuse and specular light or material properties?

Are ambient, diffuse and specular properties of light or material? I am doing ray casting in OpenGL, I've managed to create lit sphere using formula I = L Ka + L Kd (n . l) + L Ks (r . v)^n but I ...
1
vote
1answer
110 views

What is w componet [duplicate]

What is the W component on graphics programming. I read a blog about opengl that says that w must be equal to either 0 or 1 here. But the book I am currently reading has put w component to more than 1 ...
3
votes
1answer
183 views

How to Construct a Perspective Projection With 4 Vanishing Points

Is it possible to construct a projection matrix which will create a perspective with four (or more) vanishing points? This question have an OpenGL tag, but general insights are welcomed as well.
0
votes
1answer
76 views

Displaying normals of a geometry

I have a rectangle which is created by 2 triangles and it is in x-z plane, and i have object on it. Now, the normals of two triangles (face normals) are y axis i.e. (0,1,0). I want to display normals ...
0
votes
1answer
999 views

rotating 3D object around the center

I have object moving from A to B on x-axis and there is no translation of object apart from it. Now, while moving, i want to rotate it around y-axis and the motion should change accordingly, i mean if ...
1
vote
1answer
103 views

How to render models using a personalized projection matrix?

I'm creating a game with a great sprite demand. Out team is considering automatizing the sprite generation using 3D models. The problem is we have a very particular ortographic projection: We have ...
2
votes
0answers
286 views

OpenGL: Attempt to allocate a texture too big for the current hardware [closed]

I'm getting the following error: java.io.IOException: Attempt to allocate a texture to big for the current hardware at ...
1
vote
1answer
157 views

How can I find the location of OpenGL object after rotation?

I have a rotating object, a cube, which I rotate in OpenGL as follows: gl.glPushMatrix(); gl.glTranslatef(400.0f, 300.0f, 1300.0f); gl.glRotatef(m_x, 4.0f, 0.0f, 0.0f); gl.glRotatef(m_y, 0.0f, 4.0f, ...
3
votes
2answers
297 views

Using a programmable pipeline in a game engine

As a learning experience, I'm developing my own 3D game engine using OpenGL. I'm a little confused as to how to implement my rendering engine such that it uses a programmable pipeline while still ...
0
votes
1answer
826 views

Reinhard tone mapping and color space [closed]

I found two ways of doing tone mapping (first, second): //Ld - this part of the code is the same for both versions float lum = dot(rgb, vec3(0.2126f, 0.7152f, 0.0722f)); float L = (scale / ...
2
votes
1answer
362 views

RGB to xyY color space conversion and luminance

The luminance calculated by following GLSL functions (fragment shaders - tonemap) has different value: float GetLuminance (vec3 rgb) { return (0.2126 * rgb.x) + (0.7152 * rgb.y) + (0.0722 * ...
0
votes
0answers
976 views

How to do collision detection in 3D using bounding boxes?

I am using c++ in visual studio 2010 with opengl. I am trying to make a programme that has 2 boxes that are able to be stacked on top of each other but I am having some trouble with the collision ...
-5
votes
3answers
345 views

in the shadow of a sphere [duplicate]

(Related, but somewhat different, to my previous question) How can I determine in a fragment shader if a fragment is in the shadow of a sphere? That is, if it is occluded by the sphere and is past ...
0
votes
1answer
220 views

Devices or Smartphones That Can Run and Displayed Images Properly While Power of 2 Code is Disabled

Before making game apps, I want to have any certain smartphone device brands that runs on OpenGL. I have to make a code for images that doesn't need to required power of 2 images so that I can resize ...
5
votes
1answer
456 views

What are the rest of the blending functions used for?

In general, I know of five ways to make use of blending functions (these are for OpenGL, but replace glBlendFunc() with SetRenderState(D3DRS_SRCBLEND) and SetRenderState(D3DRS_DESTBLEND) for DirectX): ...
32
votes
10answers
3k views

What makes a game look “good”? [closed]

I am working on a 3D space game using OpenGL and C++ and I am planning to focus on giving the game modern, eye-catching graphics, but the more I think of it the more I realise I don't really know what ...
5
votes
1answer
872 views

What is actually drawn when glDrawArrays and glDrawElements are called?

In my journey out of immediate mode I've come across a snag that I haven't been able to find a decent answer for in any tutorial or API, namely: Which data structures are actually invoked when I make ...
0
votes
1answer
194 views

Opengl binding shaders vs binding buffers performance

Quick question for an opengl guru, I'm in the process of building a render queue and can either reduce the number of shader binding or the number of vertex buffer binding. I just want to know which ...
17
votes
3answers
2k views

What's the difference between mesh and a model?

Which one is created first? For example if a team worked on a graphical asset of a car, what would be a model and what would be a mesh of the car?
6
votes
3answers
923 views

Understanding how to create/use textures for games when limited by power of two sizes

I have some questions about the creating graphics for a game. As an example. I want to create a motorbike. (1pixel = 1centimeter) So my motorbike will have 200 width and 150 height. (200x150) But the ...
5
votes
1answer
504 views

How to flip a BC6/BC7 texture?

I have some code to load DDS image files into OpenGL textures, and I'd like to extend it to support the BC6 and BC7 compressed formats introduced in D3D11. Since DirectX and OpenGL disagree about ...
3
votes
1answer
1k views

Correct use of VAO's in OpenGL ES2 for iOS?

I'm migrating to OpenGL ES2 for one of my iOS projects, and I'm having trouble to get any geometry to render successfully. Here's where I'm setting up the VAO rendering: void bindVAO(int ...