1
vote
1answer
65 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 ...
1
vote
0answers
49 views

OpenGL ES 2.0 state management best practices [closed]

I use a game engine with dynamic sprite batching for 2D games on mobile platforms (MOAI SDK). It already handles redundant state changes pretty well - with the use of texture atlases it only flushes ...
0
votes
0answers
32 views

Barycentric vertex coordinates in GLES 2.0

I have a certain set of polygons, which are stored in a vertex buffer and an index buffer. The polygons are textureless and normalless. The polygons are dynamic, their buffers get constantly emptied ...
1
vote
2answers
90 views

Bad pixels on shader when loading cached binary programs

I have been trying to cache binary shader programs in my game and load them accordingly using "glGetProgramBinaryOES" and "glProgramBinaryOES" respectively. I was successfully able to cache and load ...
0
votes
2answers
93 views

Confusion over GLViewport

I'm hoping someone can help me understand the GLViewport and what happens when we resize it This will illustrate my confusion.... So, here I have a quad stuck in the middle of the screen. If I ...
1
vote
1answer
150 views

OpenGL and atlas

I'm trying to draw element from a texture atlas with OpenGL ES 2. Currently, I'm drawing my elements using something like that in the shader: uniform mat4 uCamera; uniform mat4 uModel; attribute ...
0
votes
0answers
96 views

Moving objects smoothly, bad perfomance

I just finished developing my mini-game on Android and I got some questions about perfomance and generally "how to": If I have 25+ objects on the creeen (just a polygon with 7-8 angles) its starts to ...
5
votes
3answers
365 views

How do I send multiple matrices to a vertex shader?

I'm practising animations using bones/skinning. I am trying to send the shader one matrix per vertex. I can think of these two approaches. Method 1 I have one uniform handle for each bone matrix ...
0
votes
1answer
61 views

What is the correct Order of Operations on OpenGL 2.0 Loading Texture in condense format?

I have come across a problem when I am loading a single texture onto a single quad, and this problem persisted during the planning phases of my project, before starting my development phase. I am ...
3
votes
1answer
136 views

Texture mapping a complex object on openGL ES

I dont have much experience with openGL ES (or openGL), but i do get the general idea of texture mapping, which is each vertex should be mapped for the relevant UV coordinates of the texture we choose ...
2
votes
1answer
236 views

How do I draw an animated object in OpenGL ES?

I have a VBO, which I initialise like this (just an example): - (void)setupVBOs { GLuint vertexBuffer; glGenBuffers(1, &vertexBuffer); glBindBuffer(GL_ARRAY_BUFFER, vertexBuffer); ...
1
vote
1answer
89 views

Run OpenGL shader on part of a texture

How do I run an OpenGL shader on just a portion of an off screen texture and leave the rest of the texture unmodified? Are there any calls that restrict the sampled pixels to just a rectangle or do I ...
0
votes
3answers
402 views

Android : glowing/pulsing line/triangle

I would like to create a simple Android app using Opengl ES 2.0 that is showing a simple shape (like line or triangle) that is glowing and pulsing like Nexus X logo in this video : ...
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 ...
5
votes
1answer
489 views

OpenGL ES 2.0 obscured texture is visible

Hi, I am using LibGDX and OpenGL 2.0 to create a game. So far I have created two meshes. The front mesh is the one with the brown circle texture and another mesh on the top with a green to white ...
0
votes
1answer
125 views

Version number not supported by gl2 in andengine

I am new to andengine. From various forums, i got to know that my system should support hardware virtulisation. I have installed "Intel X86" and my system didn't throw any problem regarding "HAX" now. ...
0
votes
1answer
174 views

OpenGLES 2.0 batching method and do not draw inactive object

I am researching about "batching" objects for one big VBO and reduce draw call. These are what I am doing now: Create interleaved VBO based on texture or render state (like Blending) So, for ...
0
votes
2answers
246 views

Which code is faster to convert -1 to 0 and 1 to 1?

I'm writing a shader for rendering the sides of triangles with different colors. I have a value mediump float back = dot(V, N) which is positive if the normal faces away from the camera and negative ...
5
votes
1answer
386 views

Sprite with alpha Blending in 3D world

I'm working on a game in a 3D world with elements 2D only (Like Don't starve game) for Android and IOS. Currently, I've managed "Sprite" without alpha blending, I've just put a condition in the pixel ...
7
votes
2answers
4k views

GLSL Shader - Change Hue/Saturation/Brightness

I'm trying to change the hue of an image using a GLSL fragment shader. I want to achieve something similar to Photoshop's Hue/Saturation Adjustment layer. In the following image you can see what I've ...
1
vote
1answer
210 views

How to deal with lot of textures in one draw call?

I'am currently developing text rendering & some kind of tile based texturing for simple landscape with textures blending. e.g. something like this but in 3D. In first realization I have been used ...
1
vote
0answers
380 views

How to implement OpenGL triple buffering

I'm trying to implement the triple buffering described here ...
1
vote
2answers
395 views

Calling glGetError() in release builds?

Currently, I'm calling glGetError() after each OpenGL function call in order to be able to detect and report bugs. I've been reading that glGetError() calls should be reduced to once per frame in ...
3
votes
1answer
735 views

Proper way to maintain Vertex Buffer Objects

I've started learning WebGL, currently I'm building a 2D lighting system, but there is some confusion going on inside my head. How the lighting works is based on this tutorial ...
3
votes
1answer
220 views

Cut a translucent square in a texture

How to remove (cut-out) a transparent rectangle in a Texture, so that the hole will be translucent. On Android I would use the Xfermodes approach: ...
1
vote
2answers
237 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 ...
0
votes
3answers
1k views

Why doesn't glBindVertexArray work in this case?

From my understanding of what glBindVertexArray does and how it works, the following code should work fine: First init: glGenVertexArraysOES(1, &_vertexArray); ...
3
votes
1answer
318 views

Fill texture with white color

How to paint texture with white color? Example what I mean: SpriteBatch.setColor changes tint only.
0
votes
1answer
172 views

OpenGL RTT FrameBuffer question and Rendering to texture while sampling it

What i need to do: Blur the selected texture and pass the texture to another effect for postprocessing. Notice that i want one texture passed all over. How do i want to do this: Bind the FBO ( ...
15
votes
2answers
562 views

OpenGL: Where shoud I place shaders?

I'm trying to learn OpenGL ES 2.0 and I'm wondering what is the most common practice to "manage" shaders. I'm asking this question because in the examples I've found (like the one included in the API ...
3
votes
1answer
735 views

exporting bind and keyframe bone poses from blender to use in OpenGL

EDIT: I decided to reformulate the question in much simpler terms to see if someone can give me a hand with this. Basically, I'm exporting meshes, skeletons and actions from blender into an engine ...
2
votes
1answer
270 views

Is there any reason not to save skinning animation data in texture?

I have thought about saving animation data in texture. I think I can save shader parameter setting and interpolation cost in CPU, and also enable animated instancing. But I couldn't find no text ...
1
vote
3answers
476 views

OpenGL are strips/fans faster for rendering or just data bandwidth

When we send data for drawing we can mark it as TRIANGLE_STRIP or TRIANGLE_FAN to reduce the number of vertices we have to specify. Now, does this actually improve the rendering speed on the graphics ...
4
votes
1answer
974 views

Multiplication for MVP matrices: Any benefits to doing so within the vertex shader?

I'd like to understand under what circumstances (if any) it is worth doing MVP matrix multiplication inside a vertex shader. The vertex shader is run once per vertex, and a single mesh typically ...
6
votes
4answers
835 views

Impact of variable-length loops on GPU shaders

Its popular to render procedural content inside the GPU e.g. in the demoscene (drawing a single quad to fill the screen and letting the GPU compute the pixels). Ray marching is popular: This means ...
5
votes
4answers
4k views

Geometry instancing in OpenGL ES 2.0

I am planning to do geometry instancing in OpenGL ES 2.0 Basically I plan to render the same geometry(a chair) maybe 1000 times in my scene. What is the best way to do this in OpenGL ES 2.0? I am ...
0
votes
1answer
354 views

Straightforward guidelines for converting OpenGL to OpenGL ES?

Is there a straightforward list of finite steps that I need to follow to convert an OpenGL program into an OpenGL ES that's used on the iPhone and iPad? I'd be using GLKit. I've seen some similar API ...
7
votes
1answer
1k views

How can I organize render and transformation data in a scalable fashion?

I am writing for OpenGL 2.0 and in the future porting to OpenGL ES 2.0. I only use VBOs and shaders (no immediate mode, no vertex arrays). I already have working solutions, they just... feel wrong. ...
9
votes
3answers
3k 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, ...
4
votes
1answer
1k views

How can I create an orthographic display that handles different screen dimensions?

I'm trying to create an iPad/iPhone game using GLES2.0 that contains a 3D scene with a heads-up-display/GUI overlaid on the top. However, this problem would also apply if I were to port my game to a ...
6
votes
2answers
1k views

Getting the number of fragments which passed the depth test

In "modern" environments, the "NV Occlusion Query" extension provides a method to get the number of fragments which passed the depth test. However, on the iPad / iPhone using OpenGL ES, the extension ...
2
votes
1answer
3k views

How can I write only to the stencil buffer in OpenGL ES 2.0?

I'd like to write to the stencil buffer without incurring the cost of my expensive shaders. As I understand it, I write to the stencil buffer as a 'side effect' of rendering something. In this first ...
3
votes
1answer
2k views

How should I move 2D objects in OpenGL ES 2?

I am a bit confused about what I need to move a basic square. Should I use a translation matrix or just change the object vertices? Which one is better? I use a simple vertex shader, gl_Position = ...