shader

I'm using the normal shader in three.js r.58, which I understand requires a normal map . However, I'm using a dynamic displacement map, so a pre-computed normal map won't work in this situation. All the examples I've found of lit displacement maps either use flat shading or pre-computed normal maps. Is it possible to calculate the normals dynamically based on the displaced vertices instead? Edit: I've posted a demo of a sphere with a displacement map showing flat normals : Here's a link to the github repo with all of my examples illustrating this problem, and the solutions I eventually found:

I have a vertex shader in which I do a texture lookup to determine gl_Position. I am using this as part of a GPU particle simulation system, where particle positions are stored in a texture. It seems that: vec4 textureValue = texture2D(dataTexture, vec2(1.0, 1.0)); behaves differently on the simulator than the iPad device. On the simulator, the texture lookup succeeds (the value at that location is 0.5, 0.5) and my particle appears there. However, on the iPad itself the texture lookup is constantly returning 0.0, 0.0. I have tried both textures of the format GL_FLOAT and GL_UNSIGNED_BYTE. Has

In implementing Blinn/Loop's algorithm on curve rendering, I realize there is a special case on Loop Curve Type. As described in their paper (subsection 4.4, page 6-7), they said the curve should be divided into two but I'm really confused how to obtain the intersection point. Here's my rendering result: As stated in the paper, this artifact occurs when either td/sd or te/se lie in between value [0, 1]. My source code: ... case CURVE_TYPE_LOOP: td = d2 + sqrt(4.0 * d1 * d3 - 3.0 * d2 *d2); sd = 2.0 * d1; te = d2 - sqrt(4.0 * d1 * d3 - 3.0 * d2 * d2); se = 2.0 * d1; if((td / sd > 0.0 && td/ sd

What is a simple pixel shader script effect to apply brightness and contrast? I found this one, but it doesn't seem to be correct: sampler2D input : register(s0); float brightness : register(c0); float contrast : register(c1); float4 main(float2 uv : TEXCOORD) : COLOR { float4 color = tex2D(input, uv); float4 result = color; result = color + brightness; result = result * (1.0+contrast)/1.0; return result; } thanks! Is this what you are looking for? float Brightness : register(C0); float Contrast : register(C1); sampler2D Texture1Sampler : register(S0); float4 main(float2 uv : TEXCOORD) : COLOR

I have pass-through vertex and fragment shaders. vertex shader void main(void) { gl_TexCoord[0] = gl_MultiTexCoord0; gl_Position = gl_ModelViewProjectionMatrix * gl_Vertex; } fragment shader void main(void) { gl_FragColor = gl_Color; } Those produce empty rendering (black not background color like glClearBuffer does). If I modify the vertex shader to set the gl_FrontColor to gl_Color it does render untouched OpenGl buffer ... with is the expected behavior of pass-through shaders. void main(void) { gl_FrontColor = gl_Color; //Added line gl_TexCoord[0] = gl_MultiTexCoord0; gl_Position = gl

目录 写在前面 【NPR】轮廓线的渲染 Surface Angle Silhouette 参数&纹理控制 Procedural Geometry Silhouette z-bias和vertex normal的方法 写在前面 本文借鉴大佬的《【NPR】漫谈轮廓线的渲染》 地址：https://blog.csdn.net/candycat1992/article/details/45577749 【NPR】轮廓线的渲染 Surface Angle Silhouette 利用viewpoint和surface normal的点乘结果得到轮廓线信息，结果越接近0，说明离轮廓线越近。在实际应用中，我们通常使用一张一维纹理来模拟，即使用视角方向和顶点法向的点乘对该纹理进行采样。 使用了两种方法实现这种技术： 一种是使用一个参数_Outline来控制轮廓线的宽度 另一种方式是使用了一张一维纹理来控制 参数&纹理控制 使用纹理为： 使用纹理控制的轮廓效果很难控制，有的地方轮廓很宽，有些地方又捕捉不到。 这种方法的 优点 在于简单快速，可以在一个Pass里得到结果，而且还可以使用texture filtering对轮廓线进行抗锯齿。 不过也有很多的 局限性 ，比如只适用于某些模型，对于像cube这样的模型就会有问题。虽然我们可以使用变量来控制轮廓线的宽度（如果使用纹理的话就是纹理中黑色的宽度）