I've never tried blur until recently, and by that i've noticed fps drop when doing box blur. My fps will go down from 4000-5000 fps to 1000-1500 fps. Currently rendering at 853x480 frame buffer and window size.
Is this normal? Oh, and i'm only rendering a basic triangle. Here's the fragment shader code (pretty much the same from open.gl):
#version 150
in vec2 fTexCoord;
out vec4 finalColor;
uniform sampler2D tex;
const float blurSizeX = 1.0f / 853.0f;
const float blurSizeY = 1.0f / 480.0f;
void main() {
vec4 col = vec4(0.0f);
for (int y = -3; y < 4; y++) {
for (int x = -3; x < 4; x++) {
col += texture(tex, vec2(fTexCoord.x + x * blurSizeX, fTexCoord.y + y * blurSizeY)) / 49.0f;
}
}
finalColor = col;
}
Thank you in advance.