diff --git a/shader/hue.frag b/shader/hue.frag index f1deeef..5486f6f 100644 --- a/shader/hue.frag +++ b/shader/hue.frag @@ -1,12 +1,36 @@ uniform sampler2D texture; -uniform lowp mat3 rotationMat; +uniform mediump float hueAdjust; varying vec2 v_texCoord; +/* Source: gamedev.stackexchange.com/a/59808/24839 */ +vec3 rgb2hsv(vec3 c) +{ + const vec4 K = vec4(0.0, -1.0 / 3.0, 2.0 / 3.0, -1.0); + vec4 p = mix(vec4(c.bg, K.wz), vec4(c.gb, K.xy), step(c.b, c.g)); + vec4 q = mix(vec4(p.xyw, c.r), vec4(c.r, p.yzx), step(p.x, c.r)); + + float d = q.x - min(q.w, q.y); + /* Avoid divide-by-zero situations by adding a very tiny delta */ + const float eps = 1.0e-10; + return vec3(abs(q.z + (q.w - q.y) / (6.0 * d + eps)), d / (q.x + eps), q.x); +} + +vec3 hsv2rgb(vec3 c) +{ + const vec4 K = vec4(1.0, 2.0 / 3.0, 1.0 / 3.0, 3.0); + vec3 p = abs(fract(c.xxx + K.xyz) * 6.0 - K.www); + return c.z * mix(K.xxx, clamp(p - K.xxx, 0.0, 1.0), c.y); +} + void main () { vec4 color = texture2D (texture, v_texCoord.xy); + vec3 hsv = rgb2hsv(color.rgb); - gl_FragColor = vec4(rotationMat * color.rgb, color.a); + hsv.x += hueAdjust; + color.rgb = hsv2rgb(hsv); + + gl_FragColor = color; } diff --git a/src/bitmap.cpp b/src/bitmap.cpp index c054cfc..96cd968 100644 --- a/src/bitmap.cpp +++ b/src/bitmap.cpp @@ -29,8 +29,6 @@ #include -#include - #include "gl-util.h" #include "gl-meta.h" #include "quad.h" @@ -856,28 +854,10 @@ void Bitmap::hueChange(int hue) quad.setTexPosRect(texRect, texRect); quad.setColor(Vec4(1, 1, 1, 1)); - /* Calculate hue rotation matrix */ - hue = wrapRange(hue, 0, 359); - float hueRad = (M_PI / 180.0f) * hue; - float x = cos(hueRad); - float y = sin(hueRad); - float a = (1.0f - x) / 3.0f; - float b = sqrt(1.0f / 3.0f) * y; - - float mat[9]; - mat[0] = x + a; - mat[1] = a + b; - mat[2] = a - b; - mat[3] = mat[2]; - mat[4] = mat[0]; - mat[5] = mat[1]; - mat[6] = mat[1]; - mat[7] = mat[2]; - mat[8] = mat[0]; - HueShader &shader = shState->shaders().hue; shader.bind(); - shader.setRotationMat(mat); + /* Shader expects normalized value */ + shader.setHueAdjust(wrapRange(hue, 0, 359) / 360.0f); FBO::bind(newTex.fbo); p->pushSetViewport(shader); diff --git a/src/gl-fun.h b/src/gl-fun.h index 21bcee6..b989ba9 100644 --- a/src/gl-fun.h +++ b/src/gl-fun.h @@ -90,7 +90,6 @@ typedef void (APIENTRYP _PFNGLUNIFORM1FPROC) (GLint location, GLfloat v0); typedef void (APIENTRYP _PFNGLUNIFORM2FPROC) (GLint location, GLfloat v0, GLfloat v1); typedef void (APIENTRYP _PFNGLUNIFORM4FPROC) (GLint location, GLfloat v0, GLfloat v1, GLfloat v2, GLfloat v3); typedef void (APIENTRYP _PFNGLUNIFORM1IPROC) (GLint location, GLint v0); -typedef void (APIENTRYP _PFNGLUNIFORMMATRIX3FVPROC) (GLint location, GLsizei count, GLboolean transpose, const GLfloat* value); typedef void (APIENTRYP _PFNGLUNIFORMMATRIX4FVPROC) (GLint location, GLsizei count, GLboolean transpose, const GLfloat* value); /* Vertex attribute */ @@ -175,7 +174,6 @@ typedef void (APIENTRYP _PFNGLRELEASESHADERCOMPILERPROC) (void); GL_FUN(Uniform2f, _PFNGLUNIFORM2FPROC) \ GL_FUN(Uniform4f, _PFNGLUNIFORM4FPROC) \ GL_FUN(Uniform1i, _PFNGLUNIFORM1IPROC) \ - GL_FUN(UniformMatrix3fv, _PFNGLUNIFORMMATRIX3FVPROC) \ GL_FUN(UniformMatrix4fv, _PFNGLUNIFORMMATRIX4FVPROC) \ /* Vertex attribute */ \ GL_FUN(BindAttribLocation, _PFNGLBINDATTRIBLOCATIONPROC) \ diff --git a/src/shader.cpp b/src/shader.cpp index 942dd6a..824454d 100644 --- a/src/shader.cpp +++ b/src/shader.cpp @@ -550,12 +550,12 @@ HueShader::HueShader() ShaderBase::init(); - GET_U(rotationMat); + GET_U(hueAdjust); } -void HueShader::setRotationMat(const float value[9]) +void HueShader::setHueAdjust(float value) { - gl.UniformMatrix3fv(u_rotationMat, 1, GL_FALSE, value); + gl.Uniform1f(u_hueAdjust, value); } diff --git a/src/shader.h b/src/shader.h index d7181e9..7b4eb02 100644 --- a/src/shader.h +++ b/src/shader.h @@ -240,10 +240,10 @@ class HueShader : public ShaderBase public: HueShader(); - void setRotationMat(const float value[9]); + void setHueAdjust(float value); private: - GLint u_rotationMat; + GLint u_hueAdjust; }; class SimpleMatrixShader : public ShaderBase