Recent questions tagged opengl

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opengl es - Why is glReadPixels() failing in this code in iOS 6.0?

The following is code I use for reading an image from an OpenGL ES scene: -(UIImage *)getImage{ GLint width; ... Why is glReadPixels() failing on iOS 6.0? Question&Answers:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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opengl - Passing a list of values to fragment shader

I want to send a list of values into a fragment shader. It is a possibly large (couple of thousand ... method that is specifically designed for this purpose? Question&Answers:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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opengl - Matrix inverse accuracy

I have a large world, about 5,000,000 x 1,000,000 units. The camera can be near some object or ... if my matrix is getting degenerated, suffer numerical issues? Question&Answers:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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opengl es - Rendering to non-power-of-two texture on iPhone

Is it possible to render to texture with OpenGL ES 1.1 on the iPhone (2G and older)? If I bind a texture as a render ... POT. Maybe it can't be done on ES 1.1? Question&Answers:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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opengl - Do conditional statements slow down shaders?

I want to know if "if-statements" inside shaders (vertex / fragment / pixel...) are really slowing down the shader ... the else and the other for the if part? Question&Answers:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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opengl - GLSL fixed function fragment program replacement

When using the OpenGL fixed function pipeline for vertex setup, how a fragment program looks like that is ... that replaces GL's fixed function shader? Question&Answers:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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opengl - How to implement 2D raycasting light effect in GLSL

This was originally asked by @sydd here. I was curious about it so I try to code it but It was ... input should be: mouse position background RGBA map texture Question&Answers:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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opengl - Rotating a Group of Vectors

I am trying to rotate a group of vectors I sampled to the normal of a triangle If this was correct, the randomly ... ); // current vector I am trying to rotate Question&Answers:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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opengl - Why transforming normals with the transpose of the inverse of the modelview matrix?

I am working on some shaders, and I need to transform normals. I read in few tutorials the way you transform normals ... so, and what is the logic behind that? Question&Answers:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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opengl - glVertexAttribPointer and glVertexAttribFormat: What's the difference?

OpenGL 4.3 and OpenGL ES 3.1 added several alternative functions for specifying vertex arrays: glVertexAttribFormat, ... ? How do the new APIs work? Question&Answers:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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opengl - Should I ever use a `vec3` inside of a uniform buffer or shader storage buffer object?

The vec3 type is a very nice type. It only takes up 3 floats, and I have data that only needs 3 floats. And I ... data2; float data3; }; Is this a good idea? Question&Answers:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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opengl - Rendering meshes with multiple indices

I have some vertex data. Positions, normals, texture coordinates. I probably loaded it from a .obj file or ... I render this mesh data using OpenGL/Direct3D? Question&Answers:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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opengl - How do I compose a rotation matrix with human readable angles from scratch?

The one thing that has always hindered me from doing 3D programming is failing to understand how math works. I can ... :400px;height:300px;">   </div> Question&Answers:os...

asked Oct 16, 2021 in Technique[技术] by 深蓝 (71.8m points)

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opengl - How do I display gluCylinder in a window?

This program can display a mesh of vertices and indices for cubes and stuff, but I don't know if I need ... .com/questions/65839462/how-do-i-display-glucylinder-in-a-window...