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Type: Posts; User: oc2k1

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  1. Replies
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    direct_state_access reloaded

    It seams to be that many people liked the EXT_direct_state_access, but unfortunately it' gone in OpenGL-3.2 or 3.1 with forward compatible bit.

    The extension self is written against 2.1 For 3.2...
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    Re: Perlin noise in a fragment shader

    Try my implementation. Unfortunately it slows down at high magnifications, but it supports anisotropic filtering...

    http://lumina.sourceforge.net/Tutorials/Noise.html
  3. Re: how to transform using shaders without deprecated?

    Build your own matrix stack replacement and use a 4x4 uniform matrix....
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    1,399

    Re: Beizer Curves : Questrion

    If start and end point aren't count as single point, a minimum of 5 points are required, because the points 0;1,n-1;n have to be placed on a straight line.

    A good replacement are 3 parabolic...
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    Minimal GLX OpenGL3.0 example

    New drivers OpenGl 3.0 capable drivers are out, but nowhere is an example to test it or start own experiments. Here is my minimal c++ example:



    #include <GL/glx.h>
    #include <GL/gl.h>
    #include...
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    Re: Placing thousands of models on a sphere..

    Deprecation of the gl matrix stuff does not mean, that using matrices is a bad idea. But emulating these functionality in a vertexshader with many instructions would...

    It's highly recommended to...
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    5,137

    Re: 3D and 1D color Lookups implementation

    varying vec2 texCoord;
    void main() {
    texCoord = gl_Vertex.xy;
    gl_Position = vec4(gl_Vertex.xy * 2.0 - 1.0, 0.0, 1.0);
    }

    and render a quad like this:
  8. Replies
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    3,373

    Re: Hexagonal mosaic filter shader

    Maybee you should correct some details:



    void main(void){
    vec4 displacment = texture2D( displacment_map,gl_TexCoord[0].xy * 20.0);
    gl_FragColor = texture2D(color_map_1,...
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    Re: Geometry Shader Interpolation

    Sure you can use many varyings:
    http://lumina.sourceforge.net/Tutorials/Geometryshader.html you have to declare the input varyings as "varying in type name[];" and the out varyings a "varying type...
  10. Thread: geometry shaders

    by oc2k1
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    4,042

    Re: geometry shaders

    My shader IDE can do geometry shaders:
    http://lumina.sourceforge.net/Tutorials/Geometryshader.html
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    Re: screen aligned quad

    use a vertexshader like this:


    void main(void){
    gl_Position = gl_Vertex * 2.0 - 1.0;
    gl_TexCoord[0] = gl_Vertex;
    }


    and draw a quad like that (or replace it by a model):
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    Re: Can FBOs share textures?

    It isn't a problem, except with CSAA render targets, because the coverage is stored into the depthbuffer
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    12,489

    Re: rotating point sprites

    Sure, but there is a good approximation possible:

    Calculate the view vector in texturespace, and use the tangent and bitangent, to shear, scale and rotate the texture coordinates.
    In that case...
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    Re: Sample use of shaders on Linux

    One possibility to use GLSL shaders with that laptop on linux would be to use MESA as software renderer.
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    Re: how to calculate tangent vector for each verte

    The dimension of the points isn't important, because the spline interpolation defines only rules to mix four of them.

    Tangents are simple too: Instead a Cubic spline the difference of two quadric...
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    6,521

    Re: Display list compilation speed

    Maybe you shouldn't call glMaterialfv between glBegin and glEnd. Check errors for GL_INVALID_OPERATION...
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    5,912

    Re: Help with Cascading Shadowmapping

    Looks like a (near) clipping problem, check your shadow volumes...
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    2,741

    Re: how to use Free-Form Deformation?

    With a vertex shader and a high enough tessellated object, it's possible. But it won't work well without a GF8/9, because previous cards are limited in uniform storage or vertex texture fetch.

    The...
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    Re: Depth buffer precision

    Here is an example:
    http://lumina.sourceforge.net/Tutorials/Depth_peeling.html

    You shouldn't store the depth into a color rendertarget, use a depth texture instead.
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    Re: gl_FragDepth computation

    Distance and Z buffer can be converted with help of two values from the projection matrix:
    Z = pm[3].z/(Zbuffer * -2.0 + 1.0 - pm[2].z) ...
  21. Thread: Deferred shading

    by oc2k1
    Replies
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    79,504

    Re: Deferred shading

    That is slower, because the multiplication with the inverse viewProjection matrix requires 16 (scalar) MADDs
  22. Thread: Deferred shading

    by oc2k1
    Replies
    69
    Views
    79,504

    Re: Deferred shading

    One of the fastest reconstruction is this:


    mat4 m = gl_ProjectionMatrix;
    float Z = m[3].z/(texture2DRect(G_Depth, gl_FragCoord.xy).x * -2.0 + 1.0 - m[2].z);
    vec3 modelviewpos =...
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    Re: Indexing tables in GLSL

    The GF8 uses unified shaders, so the fragment shaders uses the same hardware like the vertex shader. On GF7 and earlier the fragment shaders were not be be able to do that. As long the all indices...
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    Re: emulate NV_depth_clamp on ATI

    the clipping runs before the fragment shader. So the fragments are already clipped away.
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    Re: SDRC/I-DEAS won't run under OGL 2.0

    OpenGL 2.0 is backward compatible. It could be possible that the cad application checks only if the version number is equal to 1.5.
    You should post the error mesage if possible and you could write a...
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