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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GLSL Shader Effects: How to do motion blur, etc?
I am not sure how right it is to ask this question, but still here it goes.
I have a full 2D environment, with sprites going around as landscape, characters, etc
And to make it more state-of-art ...
11
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3answers
2k views
What is the difference between OpenGL 1.x and 2.x?
Is there a good tutorial that shows the difference between OpenGL 1.* and 2.*?
It would be very helpful to know which functions I should not be calling (like glBegin(), I assume).
11
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1answer
3k views
How can I tell how much video card memory I'm using?
I want to programmatically determine at runtime how much video card memory is being used by my program. Specifically I'm wondering about how to do it on a Windows machine using OpenGL, but am ...
11
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2answers
361 views
Do I lose/gain performance for discarding pixels even if I don't use depth testing?
When I first searched for discard instruction, I've found experts saying using discard will result in performance drain. They said discarding pixels will break GPU's ability to use zBuffer properly ...
11
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3answers
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How do I implement a quaternion based camera?
UPDATE The error here was a pretty simple one. I have missed a radian to degrees conversion. No need to read the whole thing if you have some other problem.
I looked at several tutorials about this ...
10
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2answers
1k views
What OpenGL version(s) to learn and/or use?
So, I'm new to OpenGL... I have general knowledge of game programming but little practical experience.
I've been looking into various articles and books and trying to dive into OpenGL, but I've ...
10
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3answers
1k views
Go pure OpenGL or GLSL?
I got interested in studying graphic programming so the obvious entry point was to learn OpenGL. But gathering scattered information around forums and sites, it seems that a pure OpenGL implementation ...
10
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3answers
2k views
Why do pixel shaders not let us read directly from the framebuffer or the depth buffer?
Letting me sample the framebuffer or the depthbuffer in the pixel shader would be an extremely useful feature. Even just being able to know the depth or the color of whatever is behind the current ...
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3answers
5k views
How can I make OpenGL textures scale without becoming blurry?
I'm using OpenGL through LWJGL.
I have a 16x16 textured quad rendering at 16x16. When I change it's scale amount, the quad grows, then becomes blurrier as it gets larger.
How can I make it scale ...
10
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3answers
5k views
Trying to understand light on Opengl, how to simulate a realistic sun light?
I don't know if I'm doing something wrong or missing anything but I want to simulate sun light, like in a sunny day.
When the object is facing the directional light, it's well lit and there's no ...
10
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2answers
578 views
What should I worry about when changing OpenGL origin to upper left of screen?
For self education, I'm writing a 2D platformer engine in C++ using SDL / OpenGL. I initially began with pure SDL using the tutorials on sdltutorials.com and lazyfoo.net, but I'm now using SDL to ...
10
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1answer
619 views
How do I create good looking plasma explosion effects?
Is this just a billboard quad with a bloom shader?
10
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2answers
2k views
Efficient skeletal animation
I am looking at adopting a skeletal animation format (as prompted here) for an RTS game. The individual representation of each model on-screen will be small but there will be lots of them!
In ...
10
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0answers
222 views
My game seems to be incompatible with recording software. What could be causing this?
I've just finished a little Game-Dev project for university and I need to record a video to accompany my submission (just in case they can't get my source to work). Basically my game doesn't work at ...
9
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3answers
2k views
Why does OpenGL >= 3 only allow VBOs?
I see that OpenGL versions 3 and up eliminate the use of client-side rendering. Immediate mode has been eliminated, and vertex arrays seem to be deprecated. Instead, if I understand correctly, VBOs ...
9
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3answers
10k views
Fastest way to draw quads in OpenGL ES?
I am using OpenGL ES 2.0
I have a bunch a quads to be drawn, would love to be able to have to pass only 4 vertices per quad as if I were using GL_QUADS, but basically I just want to know the best way ...
9
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5answers
3k views
OpenGL's matrix stack vs Hand multiplying
Which is more efficient using OpenGL's transformation stack or applying the transformations by hand.
I've often heard that you should minimize the number of state transitions in your graphics ...
9
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2answers
6k views
OpenGL ES 2.0 Point Sprites Size
I am trying to draw point sprites in OpenGL ES 2.0, but all my points end up with a size of 1 pixel...even when I set gl_PointSize to a high value in my vertex shader.
How can I make my point sprites ...
9
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5answers
544 views
API agnostic bridges (ie. OpenGL/D3D/Whatever). Do you use them, how you make them. Pro's and Con's
You are making a 3d engine. You want best of multiplatform worlds. Suddenly you realize that if you want to use Direct3D on Windows machines and OpenGL on OSX/Linux, you'll have to sacrifice supported ...
9
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1answer
281 views
How to achieve light that changes color mid-way?
I thought of creating light sources, and some colored windows. Now, the windows are semi-transparent. How could I make it so that when the light (say, pure white) hits the glass and continues through ...
9
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1answer
2k views
How does UVW texture mapping work?
I'm trying to understand the mathematical theory behind UVW mapping. Can anyone explain me how UVW mapping works? Or at least provide me a pointer?
9
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2answers
774 views
Rendering characters, with cut off limbs (Blender models in Java/OpenGL)
What aspects should I take into consideration for creating character animation and rendering classes if I want to be able to have detachable limbs? I've developed a detailed body system that can have ...
9
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1answer
1k views
How can I create a “night sky” effect in OpenGL?
I am creating a game using OpenGL and I want to render the effect of a night sky with a few stars in it.
I want to have a shiny black effect in the sky so that it looks good. Could some one help in ...
9
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2answers
6k views
converting a mouse click to a ray
I have a perspective projection. When the user clicks on the screen, I want to compute the ray between the near and far planes that projects from the mouse point, so I can do some ray intersection ...
9
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2answers
894 views
How can I unit test rendering output?
I've been embracing Test-Driven Development (TDD) recently and it's had wonderful impacts on my development output and the resiliency of my codebase. I would like to extend this approach to some of ...
9
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2answers
360 views
How does Halo draw projectiles?
I am trying to draw projectiles and doing billboarding. A projectile consists of a bill-boarded "particle" and a "tracer". When I billboard a projectile, it cannot be seen when the player's viewing ...
9
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5answers
2k views
Skybox texture artifact on edge
I have strange problem with drawing skybox texture on Mac. On iPhone everything is going fine. I have tried to change near and far planes value with no success.
It is a skybox of six textures, and ...
9
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3answers
2k views
Lighting in a Minecraftian World
Minecraft is a game that is largely based on a heightmap and uses that heigtmap information to flood the world with light. From my understanding the highest point in the heightmap is the end of the ...
9
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1answer
317 views
Modern shadow rendering techniques?
What is the state of the art in terms of shadow rendering? My target is OpenGL 3.2, using a deferred rendering pipeline, if that matters.
It's been years since I looked into shadow rendering, and at ...
9
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1answer
2k views
Generate an endless 3D race track
How would I go about generating the track for this game I'm trying to prototype?
http://www.youtube.com/watch?v=uQwn7Ufypqo
It should be an endless tunnel that sweeps along a 3D spline, with some ...
9
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1answer
250 views
Deforming surfaces
I try to accomplish an deforming physic behaviour for levelsurfaces, but don't get an idea how to start with the implemenation so far.
Regardless of the shape from the surface (planes, cubes, ...
9
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3answers
2k views
Animation in OpenGL using 3D Models
I have created a model in Blender. Now i want to read that 3D model in my c++ program. I figured that a model can be exported to various file formats e.g. .obj, .3ds or COLLADA and then can be read in ...
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6answers
1k views
Why does the resolution of floating point numbers decrease further from an origin?
My OpenGL scene has objects that are positioned at ridiculously far distances away from the origin. When I view these objects, and pan/rotate/zoom a camera around them, they 'jitter'. That is, the ...
8
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2answers
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OpenGL: VBO or glBegin() + glEnd()?
I recently was given this link to a tutorial site from someone who I gave the original OGL Redbook to. The third header down says distinctly to forget glBegin() & glEnd() as the typical render ...
8
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3answers
2k views
How can I bend an object in OpenGL?
Is there a way one could bend an object, like a cylinder or a plane using OpenGL?
I'm an OpenGL beginner (I'm using OpenGL ES 2.0, if that matters, although I suspect, math matters most in this case, ...
8
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4answers
1k views
Fixed-Function vs Shaders: Which for beginner?
I'm currently going to college for computer science. Although I do plan on utilizing an existing engine at some point to create a small game, my aim right now is towards learning the fundamentals: ...
8
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4answers
526 views
OpenGL: why do I have to set a normal with glNormal?
I'm learning some basics of OpenGL but I'm wondering why there is a call glNormal to set the normal of vertices.
If I create a simple triangle like this:
glBegin(GL_TRIANGLES);
...
8
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5answers
3k views
What version of OpenGL should I code for, given compatibility and performance considerations?
When the OpenGL spec is updated, they only ever add features. So in theory, the latest and greatest hardware with support for the Core and Compatibility profiles should run super old OpenGL1.1 code ...
8
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4answers
579 views
I need help with 3d shading/lighting
How do you guys handle shading in a 3d game? I have a directional light source that shades one side of a tree made of cubes. The remaining 3 sides all get ambient shading only. So the 3d effect is ...
8
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1answer
664 views
OpenGL vs physics?
I am very new to game programming and I am in my first project. I have come to a point that I need expert advice:
Now for the game physics to be able to work on objects, it needs to know each ...
8
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4answers
12k views
Writing Game Engine from scratch with OpenGL
I want to start writing my game engine from scratch for learning purpose, what is the prerequisites and how to do that, what programming languages and things you recommend me? Also if you have good ...
8
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1answer
300 views
How to reduce image size without pixelation?
I see lots of games with smooth edges characters and high res images, however when I try to reduce images to say 64x64 for my character I just get a pixelated mess. even if I start with a 64x64 canvas ...
8
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5answers
6k views
Drawing lots of tiles with OpenGL, the modern way
I'm working on a small tile/sprite-based PC game with a team of people, and we're running into performance issues. The last time I used OpenGL was around 2004, so I've been teaching myself how to use ...
8
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1answer
272 views
Mesh manipulation on GPU vs CPU
Just a bit curious - where do you perform mesh manipulations, on the CPU or in the shader?
I've been doing everything on the CPU and a friend suggested moving things on to the GPU side.
If you're ...
8
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2answers
448 views
What is the primary use of Vertex Buffer Objects?
From what I've read, it seems VBOs are purely for performance.
I'm working on a very rudimentary learning project in lwjgl and I'm just trying to figure out what more advanced features of the library ...
8
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1answer
2k views
differences between opengl 3 and opengl 4
I'm just getting started with game programming and I want to start learning opengl. I found a very great tutorial from scratch to get started with opengl 3 and I'm wondering if there is a big ...
8
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2answers
512 views
Handle many lights in a scene (with shaders)
I'm curious about how to handle many lights in a scene. Given a very big map in a role playing game, with dungeons (with lights in there) etc. I know about deferred lighting, but that only answers how ...
8
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1answer
262 views
OpenGL: Light at end of tunnel effect
Anyone knows any implementation of the "light at the end of tunnel" effect? where the outside is entirely bright and gradually becomes more visible?
The reverse could also be true, where the inside ...
8
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1answer
438 views
Rendering 8 bit graphics
I have a strong programming background just not from game development. I only made some pong and snake in high school and I did some OpenGL in college.
I want to make my own game engine. Nothing ...
8
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1answer
807 views
Getting OpenGL hardware acceleration with SDL on Linux
I'm trying to use SDL + OpenGL but I don't believe hardware acceleration is working because the framerate for around 18000 polys is about 24fps on a quad core machine but is a hopeless 1-2fps on an ...
