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I would like to leave OpenGL's lights and make my own. I would like my shaders to allow for a variable number of lights.
Can we declare an array of uniforms in GLSL shaders? If so, how would we set the values of those uniforms?
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To initialize an array you can use a constructor. Like in object orientation GLSL has a constructor for arrays. The syntax is as follows. int a[4] = int[](4, 2, 0, 5, 1); float a[5] = float[5](3.4, 4.2, 5.0, 5.2, 1.1); int[] c = int[3](1, 2, 3); int[] d = int[](5, 7, 3, 4, 5, 6);
A uniform is a global Shader variable declared with the "uniform" storage qualifier. These act as parameters that the user of a shader program can pass to that program. Their values are stored in a program object.
GLSL does not support anonymous structures (ie: structs without a type name), and structs must have at least one member declaration. Structs cannot be defined within another struct, but one struct can use another previously defined struct as a member.
According to the OpenGL wiki, a uniform is “a global GLSL variable declared with the 'uniform' storage qualifier.” To be a little more specific: your shader executes on the GPU, which is physically distinct from the rest of the computer, separated by a bus.
Yes this is possible. You declare uniform arrays similar to how you'd do it in C, e.g.
uniform float v[10]; Then you can set their values using glUniform{1,2,3,4}{f,i}v
GLfloat v[10] = {...}; glUniform1fv(glGetUniformLocation(program, "v"), 10, v); Yes it is possible to declare an array of uniforms in GLSL shaders. Just google "glsl uniform array" for some examples (edit: or see datenwolf's example). There are however limitations on how many uniforms can be sent to different graphics cards (at least on older ones, I'm not sure about current ones (although I imagine there still would be)).
If you do decide to go down the route of uniforms, i would suggest using uniform buffers. According to http://www.opengl.org/wiki/Uniform_Buffer_Object, "Switching between uniform buffer bindings is typically faster than switching dozens of uniforms in a program".
If you have large numbers of lights and parameters, you could also send the data as float buffers.
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