I want to do a fisheye effect on android useing opengl 2.0,i can do it not use the opengl,but this not i want ,because this is inefficient and not support video texture. I also test the fisheye effect using Android Media Effects API,but the effect looks not good.
i also search fishshader as follows:
private static final String FISHEYE_FRAGMENT_SHADER =
"precision mediump float;\n" +
"uniform sampler2D u_Texture;\n" +
"uniform vec2 vScale;\n" +
"const float alpha = float(4.0 * 2.0 + 0.75);\n" +
"varying vec2 v_TexCoordinate;\n" +
"void main() {\n" +
" float bound2 = 0.25 * (vScale.x * vScale.x + vScale.y * vScale.y);\n" +
" float bound = sqrt(bound2);\n" +
" float radius = 1.15 * bound;\n" +
" float radius2 = radius * radius;\n" +
" float max_radian = 0.5 * 3.14159265 - atan(alpha / bound * sqrt(radius2 - bound2));\n" +
" float factor = bound / max_radian;\n" +
" float m_pi_2 = 1.570963;\n" +
" vec2 coord = v_TexCoordinate - vec2(0.5, 0.5);\n" +
" float dist = length(coord * vScale);\n" +
" float radian = m_pi_2 - atan(alpha * sqrt(radius2 - dist * dist), dist);\n" +
" float scalar = radian * factor / dist;\n" +
" vec2 new_coord = coord * scalar + vec2(0.5, 0.5);\n" +
" gl_FragColor = texture2D(u_Texture, new_coord);\n" +
"}\n";
this is i want to ,but i donot know how to use it .Can someone give me some clue.