Based on the recommendations by Tommy, Pivot, and rotoglup, I’ve implemented some optimizations which have led to a doubling of the rendering speed for the both the depth texture generation and the overall rendering pipeline in the application. First, I re-enabled the precalculated sphere depth and lighting texture that I’d used before with little effect, … Read more
You need at least Mac OS X Lion (OS X 10.7 or higher) for the basic support of OpenGL 3.2. To use the OpenGL 3.2 Core Profile, just add glutInitDisplayMode(GLUT_3_2_CORE_PROFILE | … | …); in your main-function. You can check it by std::printf(“%s\n%s\n”, glGetString(GL_RENDERER), // e.g. Intel HD Graphics 3000 OpenGL Engine glGetString(GL_VERSION) // e.g. … Read more
Sorry, it hasn’t been replaced with anything. The first idea coming to my mind for emulating it would be the geometry shader. You feed the geometry shader with a line, compute its screen space length and based on that you generate a variable number of sub lines between its start and end vertex. EDIT: Perhaps … Read more
All you need are the barycentric coordinates, since you are dealing with triangles. Assign each vertex of the triangle an identity, and then use the hardware’s built-in interpolation between the vertex and fragment stages to figure out the relative distance from each of the vertices in your fragment shader. You can think of the barycentric … Read more
GL_UNPACK_ALIGNMENT specifies the alignment requirements for the start of each pixel row in memory. By default GL_UNPACK_ALIGNMENT is set to 4. This means each row of the texture is supposed to have a length of 4*N bytes. You specify a 2*2 texture with the data: 255, 0, 0, 255, 0, 0, 255, 0, 0, 255, … Read more
You can bitshift by multiplying/dividing by powers of two. As pointed out in the comments the approach I originally posted was working but incorrect, here’s one by Aras Pranckevičius, note that the source code in the post itself contains a typo and is HLSL, this is a GLSL port with the typo corrected: const vec4 … Read more
well lets start with Real domain and integer b only: a^^b = a^a^a^a^a…^a // a is there b times this can be evaluated like this in C++: double tetration(double a,int b) // a^^b = a^a^a^a… b times { double c; if (b<=0) return 0; for (c=a;b>1;b–) c=pow(a,c); return c; } as You already got the … Read more
If you have to following rectangle, where the red cross is the center of the world and you want to rotate it around the green pivot then you’ve to do the following steps: Translate the rectangle in that way that way, that the pivot is on the origin of the world. This is a translation … Read more
Can you use C++11? If so you could use raw string literals: const GLchar* vert = R”END( #version 120 attribute vec2 position; void main() { gl_Position = vec4( position, 0.0, 1.0 ); } )END”; No need for escapes or explicit newlines. These strings start with an R (or r). You need a delimiter (I chose … Read more
I’d like to extent on BDL’s answer. It is not only about the perspective interpolation. It is also about the clipping. The space the value gl_Position is supposed to be provided in is called clip space, and this is before the division by w. The (default) clip volume of OpenGL is defined in clip space … Read more