'texture2D' : function is removed in Forward Compatibile context
c++, glsl, opengl
Solution
The error says everything you need to know. `texture2D` is an old function from the GLSL 1.00 days. It was removed and replaced with `texture`, which uses function overloading to work on most sampler types, rather than being restricted to `sampler2D`. So in a core profile or forward compatibility context, you cannot call `texture2D`.
Problem
I am trying to implement 5x5 convolution filter (Find Edges) using `GLSL` here is my code of `.glsl` source: ``` #version 150 #define SIZE 25 // A texture is expected uniform sampler2D Texture; // The vertex shader fill feed this input in vec2 FragTexCoord; // The final color out vec4 FragmentColor; float matr[25]; float matg[25]; float matb[25]; vec4 get_pixel(in vec2 coords, in float x, in float y) { return texture2D(Texture, coords + vec2(x, y)); } float convolve(in float[SIZE] kernel, in float[SIZE] matrix) { float res = 0.0; for (int i = 0; i < 25; i++) res += kernel[i] * matrix[i]; return clamp(res, 0.0, 1.0); } void fill_matrix() { float dxtex = 1.0 / float(textureSize(Texture, 0)); float dytex = 1.0 / float(textureSize(Texture, 0)); float[25] mat; for (int i = 0; i < 5; i++) for(int j = 0; j < 5; j++) { vec4 pixel = get_pixel(FragTexCoord,float(i - 2) * dxtex, float(j - 2) * dytex); matr[i * 5 + j] = pixel[0]; matg[i * 5 + j] = pixel[1]; matb[i * 5 + j] = pixel[2]; } } void main() { float[SIZE] ker_edge_detection = float[SIZE] ( .0,.0, -1., .0, .0, .0, .0,-1., .0, .0, .0, .0, 4., .0, .0, .0, .0, -1., .0,.0, .0, .0, -1., .0, .0 ); fill_matrix(); FragmentColor = vec4(convolve(ker_edge_detection,matr), convolve(ker_edge_detection,matg), convolve(ker_edge_detection,matb), 1.0); } ``` When I run my code it gives me errors: ``` Error Compiling Fragment Shader ... ERROR: 0:17: 'texture2D' : function is removed in Forward Compatibile context ERROR: 0:17: 'texture2D' : no matching overloaded function found (using implicit conversion) Error Linking Shader Program ... Attached fragment shader is not compiled. Function is removed in Forward Compatibile context ``` Weird thing is, when I've tried to run code on other linux and then windows machines it just worked fine. Also when I changed `texture2D` in `get_pixel()` function to return `texture` only it worked like a charm. Could someone explain where is a problem?