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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What is the purpose of bitdepth for the several components of the framebuffer in glfwWindowHint function of GLFW3?

I would like to know what are the following "framebuffer related hints" of GLFW3 function glfwWindowHint : GLFW_RED_BITS GLFW_GREEN_BITS GLFW_BLUE_BITS GLFW_ALPHA_BITS GLFW_DEPTH_BITS ...
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1k views

glBufferSubData and offset alignment?

I'm having trouble rendering some of my meshes; some display just fine, some are drawn wrong or not at all. While troubleshooting I was looking at the openGL docs ...
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2answers
139 views

Calling opengl32.DLL from java?

I don't like LWJGL in some cases, so I prefer to use Swing. The thing is that Swing doesn't have OpenGL. I have tried JOGL and it's a mess to install, needs external jars, and I have yet to get it ...
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541 views

How to rotate a direction

I'm working a spotlight for my deferred renderer and I'm having trouble with matching the mesh to the visual representation of the light. Right now my mesh is a cone, the apex of the cone is at ...
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390 views

Indoor 3D game worlds

I'm looking for a little direction. I'm building a game engine as a part of my university project, and I'm having a little trouble about what to look for when it comes to indoor 3D game worlds. Now ...
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547 views

Event Based Render / Update Loop

I'm working on a few game dev tools which use OpenGL or DirectX to render 3D models (viewing). Consider your favorite 3D modeling software package (Softimage, Maya, 3DS Max, modo, etc.). Note that ...
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2answers
276 views

Deferred rendering order?

There are some effects for which I must do multi-pass rendering. I've got the basics set up (FBO rendering etc.), but I'm trying to get my head around the most suitable setup. Here's what I'm ...
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1answer
2k views

LWJGL - Mixing 2D and 3D

I'm trying to mix 2D and 3D using LWJGL. I have wrote 2D little method that allow me to easily switch between 2D and 3D. protected static void make2D() { glEnable(GL_BLEND); ...
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165 views

Artifacts when draw particles with some alpha

I want to draw in my game some particles. But when I draw one particle above another particle, alpha channel from this above "clear" previous drawed particle. I set in OpenGL blend in this way: ...
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2answers
552 views

Sharing VBO with multiple objects and fixed size buffer data

I'm just messing around with OpenGL and getting some basic structures in place and my first attempt resulted in each SceneObject class (just contains vertex information right now) having it's own VBO ...
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1answer
201 views

Can I limit the number of shader units used by my video card?

Can I limit the number of shader units used by my video card? (A shader unit is the part of the hardware which can execute a shader program, where each unit runs in parallel). I'm interested in this ...
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143 views

OpenGL Shading Program Object Memory Requirement

gDEbugger states that OpenGL's program objects only occupy an insignificant amount of memory. How much is this actually? I don't know if the stuff I looked up in mesa is actually that I was looking ...
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812 views

Rotating a polygon around it's center

I have drawn a ship using three lines, and would like to rotate the ship around its axis in opengl, I have tried the following, but the ship translates while rotation!. void Ship::Draw( ) { ...
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358 views

Simplified trajectory equation to identify Time Taken(t) by a protectile to travel Distance(d), under gravity?

I am building a game, where I have to plot a trajectory of a ball in 3D space, launched with an inital velocity Sx, Sy, Sz. [I am using OpenGL and Android-NDK] Lets assume Sz is always 0. And Sx ...
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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
585 views

Cascade(Waterfalls) particles animation - openframeworks, alternatives

Has anyone tried to create a waterfall particles animation using openframeworks? Is it possible? Is it good? If not, can you recommend any other frameworks for easier creation of cascade animation? ...
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1answer
2k views

“Unable to create OpenGL 3.3 context (flags 0, profile 1)”

Trying to run any of the well-known McKesson's tutorials on a friend's laptop results in the aforementioned exception. I read that in order to run applications which use OpenGL 3.3 you must at least ...
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1answer
435 views

Erasing part of lines in libgdx with ImmediateModeRenderer

Hi i'm using the ImmediateModeRenderer renderer = new ImmediateModeRenderer10(); to render a line with the next block renderer.begin(matrix, GL10.GL_LINES); renderer.color(color.r, color.g, ...
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2answers
2k views

Back-face culling in 2d openGL game

I have a 2d game I've made using openGL ES. The game contains a large quad that fills the entire screen (as a background image) and many smaller quads that make up a number of balls that bounce across ...
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2answers
4k views

FBO Depth Buffer not working

I'm trying to get the depth buffer for my 2D game working by offsetting the z value of the rectangles. For some reason, my depth buffer is coming back empty. The value is always 0. I'm assuiming there ...
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1answer
780 views

glsl applying shader

I want to use a shader just for learning purposes. But i have a few questions about it. I have the following code: Vertext shader: const float Eta = 0.66; // Ratio of indices of refraction ...
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1answer
1k views

OpenGL relative 2D camera

Some days ago, I've felt a need to add a camera to my game, it's a puzzle. That would let me move the board, zoom in and etc. This gave me control to do boards muuuch larger, soon, more complex ...
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1answer
196 views

Why is texturing interfering with my ID-based picking implementation?

Today I came across a tutorial about color picking and I implemented it on my machine. But there is a problem: when I disable the texture and draw the object I want to pick with its picking color, it ...
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1answer
2k views

Detect two specific objects collision with bullet physics

I have got some problem with defining collision between objects in my game using bullet physics. I know that objects are colliding with each other simultaneously and I don't have to do anything more. ...
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3answers
3k views

3D picking lwjgl

I have written some code to preform 3D picking that for some reason dosn't work entirely correct! (Im using LWJGL just so you know.) I posted this at stackoverflow at first but after researching some ...
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1answer
3k views

Picking objects with mouse ray

I simply want to pick a few spheres in my scene using the mouse-ray. I have implemented(copied most of it but with little understanding) a ray-sphere collision code. Also I have implemented the code ...
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681 views

Checking Collisions In 2D Platformer With Tiles

My team and I are developing a 2D platformer with C++/SDL/OpenGL, and we already defined a collision system, but we have a problem checking collisions with the tilemap. The tiles of the tilemap are ...
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1answer
249 views

Frame Buffer Objects vs calling TexCoord2f?

I'm learning the basics of OpenGL with lwjgl currently, and following a guide I've got textured quads that can move around a scene. I've been reading about Frame Buffer Objects, and I'm not really ...
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1answer
375 views

Time calculation between openGL update calls

In XNA, the system calls update and draw function with the time information. This contains information such as how much time has passed since last update was called. This makes easy to integrate time ...
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2answers
7k views

Tips for writing 3D Collision detection with opengl

I would like to any tips/articles/tutorials on how to write collision detection using OpenGL and C++ in 3D mainly just simple box collisions etc but also if there are any advanced resources that would ...
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2answers
524 views

2d game tools , what to work on first?

My friend and I would like to program a 2D game. We were discussing about tools needed, so while I am working on the tools, he will work on game logic and stuff. Probably I will put our tools into the ...
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2answers
2k views

why specular light is not running?

i'm on JOGL this is my method for lighting: private void lights(GL gl) { float[] LightPos = {0.0f, 0.0f, -1.0f, 1.0f}; float[] LightAmb = {0.2f, 0.2f, 0.2f, 1.0f}; float[] LightDif = ...
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843 views

OpenGL FBO Rendering

I'm getting some artifacts when I try to use a colour attachment on an FBO. I'm saving my first pass as a texture, then passing it as an input to an anti-aliasing shader. The result is, as below, some ...
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1answer
81 views

How do I add a border to rectangles using a shader?

I want to draw some rectangles with a border. Currently I render the fill with glDrawArrays(Triangles, ...) and the border with glDrawArrays(LineLoop, ...). Is there a neater way? I'm targeting ...
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1answer
63 views

Draw selected instances of VAO (glDrawArraysInstanced)

I'm using glDrawArraysInstanced to draw multiple instances of a tree at different positions to generate a forest. Is there a way to draw selected instances? For example: I got 100 trees with ...
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1answer
67 views

Vertex shader in OpenGL/GLSL - transformation of the interior of a textured quad

I have a LWJGL project and ran into a problem with a vertex shader I wrote. In my scene I am rendering a map whose ground consists of rectangular tiles. On top of that there are other objects (I used ...
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1answer
65 views

Geometry Shader only creates one primitive

I am currently trying to use the geometry shader. My input is a set of points, for which multiple triangle should be created This is the geometry shader #version 330 layout(points) in; ...
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1answer
126 views

Should all primitives be GL_TRIANGLES in order to create large, unified batches?

Optimizing modern OpenGL relies on aggressive batching, which is done by calls like glMultiDrawElementsIndirect. Although glMultiDrawElementsIndirect can render a large number of different meshes, it ...
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1answer
97 views

How to create a regular grid of triangles correctly?

I am trying to create an terrain using opentk/opengl. I have a problem with the VBO/IBO. I think a picture of the problem is the best way to show it: I dont understand why the last triangle of a ...
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2answers
97 views

Keeping ratio the same across devices on fixed screen game

My game is an Android game using OpenGL ES 2.0 (But this question could apply to any platform). I have read many questions on here regarding ratio management, and also read many tutorials outside of ...
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1answer
36 views

How should I handle a modelview stack with multiple shader programs involved?

I'm building a framework where each object has an associated program and each object has a 'draw' method. What is the best choice, to have a single modelview stack handled by a Renderer class or to ...
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1answer
41 views

vertex is bending inwards

I am trying to draw a picket fence, but the center of the picket vertex looks bent in the middle, why is the picket bending inwards to the left? // draw fence pickets float a; for (a=-25; a<=25; ...
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1answer
87 views

Gamma Space and Linear Space with Shader

I am using Unity and I can choose between two color space mode in the settings: Gamma or Linear Space. I am trying to build a Custom Lighting Surface shader but I am facing some problems with those ...
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1answer
274 views

How can I implement beam effects like these?

I am interested in the techniques I could use to create the following effects: Can I accomplish this with a particle system or a series of texture quads, or what? You can see this effects in ...
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1answer
196 views

How to save am image of a screen using JOGL

Hope this is a better place to ask things like this. I have a 2D scene with some sprites drawn in Swing frame. I need them to be saved as an image. The problem is every tutorial I found seem to be ...
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1answer
41 views

Having trouble setting color in fragment shader

For some reason, the color isn't applying to the object. Here's my fragment shader code. There's probably something obvious wrong with it that i'm not seeing. #version 330 core out vec3 Color; ...
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1answer
94 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 ...
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1answer
89 views

Is there a way to use other fonts, besides the default ones in OpenGLUT?

I'm using OpenGLUT functions like glutBitmapString to render sentences and words in a game. However, there is a limited set of fonts to use and I need some bigger size fonts. Is there a way to add new ...
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1answer
131 views

Why is the light following my camera around?

I have implemented a simple Phong shader without specular highlights for now (just ambient + diffuse components) The problem however, is that the calculations seem to be done in camera space; as I ...
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1answer
93 views

In glsl, how do indices work?

I have made a vertex shader and fragment shader and kind of know how they work, and I know that you specify what index you want your vertices to be in inside the shader program. So if the vertex was ...