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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912 views

Marching Cubes Terrain [closed]

For the past week I've been researching the Marching Cubes algorithm. I hope to use this for Terrain as it would allow the creation of destruction of terrain. After looking at source code and reading ...
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266 views

LWJGL - If I use VBOs what can I do about separate textures?

So basically this is my problem: I am creating a game that needs a texture for each object. Now I would use a sprite sheet but the textures are different sizes. I am using VBOs and I need to some how ...
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1k views

Calculate object coordinates from window coordinates using inverse projection matrix

What I am trying to to is placing 3D Objects (A Sphere) in the world when I click there. I am using a perspective projection so the first step after calculating the canonical clip coordinates from ...
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1k views

How expensive is OpenGL Texture Binding

I'm currently working on a renderer for Tiled's .tmx maps. Among one of the features there is that layers and tilesets are independent, so that a layer can use any tile set on any tile. It's not so ...
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1answer
545 views

Obj Blender Export Recommendation for OpenGL C++

I have been modelling some objects inside blender, like a light bulb. I finished the light bulb, and I got a question at the time of export it. I want to export the light bulb in the wavefront format ...
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799 views

LWJGL MouseY Coordinates are flipped

So I'm very new to using OpenGL and LWJGL, although I am proficient in Java itself. One of the first things I read in the documentation of the Display class was that it maps the origin to the bottom ...
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296 views

Using OpenGL GLEW within Unity

Edit:- How do I implement GLEW (or OpenGL extension libraries) within Unity? Original Question:- I've recently been looking into some really nice features of OpenGL 3.2 that I want to take ...
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1answer
2k views

GLSL - rewriting (geometry) shader from #330 to #130 version

I'm having trouble running example from: https://raw.github.com/progschj/OpenGL-Examples/master/07geometry_shader_blending.cpp My graphics card supports only #130 shaders version so I have to rewrite ...
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9k views

SDL for 3D game programming?

I have been studying SDL for a few weeks and I have succeeded in making a 2D Ping-Pong game, but I want to get started in 3D development, and I'd like to know if SDL is capable (and suitable) for 3D ...
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1answer
930 views

How can I add a parallax effect into my side-scrolling game? [duplicate]

How can I add a parallax effect into my side-scrolling game? I read a lot about parallax scrolling so I know what the logic is and what parallax is but I can't create a dynamic parallax effect. I ...
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528 views

Chessboard colors with VBO

I am trying to draw a chessboard pattern using VBO. Geometrywise, I have it implemented and working nicely. However, I have come to the point where I want to color up the board and I have realized ...
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3k views

matrix 4x4 position data

I understand that a 4x4 matrix holds rotation and position data. The rotation data is held in the 3x3 sub-matrix at the top left of the matrix. The position data is held in the last column of the ...
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What is an appropriate OpenGL(ES)-based game engine meeting these criteria?

I want to try my hands on a little shooter on the Android platform, and I'm looking for a full-featured 3D game engine. I can't afford to pay more than 400 € for a license, so expensive engines are ...
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276 views

how could RTT be so slow on my intel card?

I simply draw something into a render target, and use it as an normal texture. It's always working greate to me with my nvidia video card. But today I found my program ran terribly slow (less than 5 ...
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1answer
151 views

OpenGL (ES 2.0) Function Dependencies

In OpenGL (ES 2.0), there are many functions that can be called in any order, and still others that must be called after other functions had been called and not before. For example, attaching a shader ...
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314 views

How to detect graphics API at runtime with SDL2?

Using SDL2, is there a way to determine at runtime whether the application is using OpenGL, OpenGLES, or DirectX? EDIT: If there is a way to figure it out without using the SDL2 API, I'm willing to ...
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1answer
163 views

Game development for high-school with C++ and OpenGL [closed]

I've been teaching high-school students (12th grade) game programming in the last 2 years. The way I did this till now, was first to give them "half made" classes (for Point, Polygon, etc.) and ...
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1answer
84 views

OpenGL - Buffer Usage

I am currently working on a little OpenGL project. At the moment I am trying to find a good solution for rendering multiple objects. I have set up a terrain with its own buffers, which works just ...
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173 views

OpenGL flickerinng near the edges

I am trying to simulate particles moving around the scene with OpenCL for computation and OpenGL for rendering with GLUT. There is no OpenCL-OpenGL interop yet, so the drawing is done in the older ...
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1answer
130 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 ...
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1answer
163 views

What should I do when a VBO becomes too large in OpenGL?

Currently I have one buffer for my vertex data and one buffer for normals data. I fill them and then pass them to OpenGL for rendering. The problem is when I load too large mesh file like "Lucy" from ...
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1answer
103 views

Given face normal and vertices of a triangle, how to find the acyclic order of vertices?

I'm in the process of constructing a custom 3D triangle mesh. I found the vertices of the triangle in the 3D space and it's face normal. How do I find the acyclic order of vertices? If I draw the ...
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1answer
552 views

How can I calculate a terrain's normals?

Im trying to implement basic lighting in Opengl 3+ (a sun) with this tutorial : http://www.mbsoftworks.sk/index.php?page=tutorials&series=1&tutorial=11 Im building a basic terrain and its ...
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1answer
139 views

opengl offscreen rendering in linux is slow [duplicate]

My opengl application runs at about 110 fps. The moment I add off-screen rendering, it slows down to 15 fps. I am using frame buffer objects and glReadPixels to render off-screen. I have searched on ...
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143 views

Anisotropic filtering on gbuffer textures for shading pass?

I have a OpenGL 3.3 deferred shader. For my geometry pass I have diffuse textures and/or normal map textures from my models and here I use max anisotropic filtering. But in my shading pass, where the ...
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1answer
316 views

lighting for landscape

I've got a landscape(created in Photoshop .raw file) and a .tga texture for it. I read .raw file and read .tga file like this LoadRawFile("landscape.Raw", MapSize * MapSize, &HeightMap[0][0]); ...
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541 views

How can I create a VBO when I don't yet know how many vertices it will contain?

I'm trying to convert my 3D block work rendering from immediate mode and display lists to VBOs. I'm having trouble understanding how to properly handle creating the buffers: I really don't know how ...
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237 views

Why swapping buffers takes different amounts of time?

When my program starts, almost nothing is on screen, just couple of lights and spheres. My FPS is at ~50. The Speed measurements looks like this: UpdateFrame took 0 ms Clearing lights queue: 0 ms ...
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1answer
144 views

SFML image extension for best performance

I am using SFML library in my 2D game. The Texture Class has a method to load an image from file: Texture.loadFromFile("image.*") Which file extension should I use to achieve best performance? ...
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1answer
115 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 ...
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3answers
2k views

Replace glTranslatef and glRotatef with matrixes

I'm not an opengl expert, and, as a novice, I prefer to practice a little bit with the old opengl just to be sure to understand correctly the basic concept of computer graphics before deal with ...
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1answer
154 views

Using an FBO texture and write to it

I wanted to know if it's possible to use a texture of an FBO for post-processing and using that texture again for writing or do I need at least two textures? I hope you understand what I mean.
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3answers
1k views

OpenGL tile rendering

Currently I'm trying to render a TileMap using OpenGL 2.1, GLSL 1.2. I would like to draw every tile in just one draw call. I use a single texture with all tiles, identifying each one by an index. ...
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1answer
250 views

How can I use OpenGL and D3D to render to the same window at the same time?

I have main render loop in which initial drawing is done via OpenGL to an SDL window, and after that the same window handle is passed to a Direct3D device, which does subsequent rendering. Once I ...
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1answer
147 views

OpenGL light not shining quad

I've constructed a scene using OpenGL/GLUT with a spot light but I'm getting troubles with light shining some of the walls what is going on and how to solve?
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1answer
243 views

Why does my blur shader implementation produce this strange result?

I tried to implement the blur shader shown here. Instead of having a simple 2D texture I use Unity's GrabPass function to capture what's behind the plane to have a transparent effect. Then I apply ...
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1answer
869 views

Drawing Sprites in Android OpenGL efficiently?

I want to basically give myself some sprite drawing functions (making use of openGL) such as; draw(Texture,x,y) I want to do this using OpenGL-ES 2.0 on Android. Since the textures can be varying ...
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2answers
272 views

How to get a texture from current point of view in OpenGL 2.0 ES?

Probably the title is confusing, but I didn't know how to ask better, sorry about that. What I would like to do is get a bitmap texture that represents exactly what's rendered at one point in time and ...
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1answer
348 views

Collision Detection Tips

I need collision detection for my 3D racing game but it isn't going well right now. I think I understand the concept of testing boxes and generating a response, however implementation part is a ...
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1answer
504 views

How to pick a 3D object with known mouse coordinates if the camera is rotated 60 degrees?

I am making a simple game engine for a simple RTS game and would like to be able to pick a cube and move it around with the mouse coordinates. The problem is that my camera is rotated 60 degrees just ...
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2answers
469 views

What's wrong with this turn to face algorithm?

I implement a torpedo object that chases a rotating planet. Specifically, it will turn toward the planet each update. Initially my implement was: void move() { vector3<float> to_target ...
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1answer
953 views

Creating a 3D text mesh from a 2D glyph

I have thought of three steps for doing this: Acquire the vertex coordinates which will represent the glyph's form Extrude them Render Can you suggest a better method? Can you give me an insight ...
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2answers
2k views

Which one have to use Canvas or Open GL for 2D game in Android

I am compleatly new to android gaming.I want to develop a 2D game with some physics in it.I want to know which one i have to use Open GL or Canvas and the reason for selection I want to include a ...
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2answers
749 views

LWJGL GL_QUADS texture artifact

I managed to get working LWJGL in Java, and I loaded a test image (tv test card), but I keep getting weird artifacts outside the image. Code: glBegin(GL_QUADS); glTexCoord2f(0, 0); glVertex2i(10, ...
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2answers
4k views

Transparent parts of texture are opaque black instead

I render a sprite twice, one on top of the other. The sprites have transparent parts, so I should be able to see the bottom sprite under the top sprite. The transparent parts are black (the clear ...
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2answers
1k views

Render a polyline with rounded joints

I have a list of points (3D) and want to draw a line connecting all points with a specified width. The line should be rendered in OpenGL (using OSG) as triangles. The real challenge of this task is to ...
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2k views

Optimized algorithm for line-sphere intersection in GLSL

Well, hello then! I need to find intersection between line and sphere in GLSL. Right now my solution is based on Paul Bourke's page and was ported to GLSL this way: // The line passes through p1 and ...
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688 views

SAT, How Do I Find The Penetration Vector?

I've just successfully implemented Separating Axis Theorem (SAT) in my game but I was wondering how do I find the penetration vector? I heard it can be useful for collision response. e.g. The harder ...
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2answers
354 views

What do I need to know for writing code for both OpenGL and OpenGL ES 2.0

I am developing an engine that uses both OpenGL and OpenGL ES 2.0. I am well seasoned in OpenGL but not ES (although I am aware it is a subset of OpenGL). I could not find a set of differences that I ...
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3answers
2k views

Walkin on terrain - Opengl

i wanna walk to terrain... first i created the terrain void desenha_terreno(float px, float pz){ for (int z = 0; z < iwidth-1; z++) { glBegin(GL_TRIANGLE_STRIP); for (int x = 0; x < ...