added texel set and get functions for texture data

include/ACGL/OpenGL/Data/TextureData.hh

@@ -77,6 +77,16 @@ public:
 
     //! flips the image horizontally as some image formats have a different coordinate system as OpenGL has.
     void flipHorizontally();
+
+    //! returns the texel converted to float (0..1 in case the data was int, -1..1 in case it was unsigned int).
+    //! If the Image had less than 4 components it get's filled with (0,0,0,1)
+    //! _texCoord is NOT normalized to 0..1! and gets clamped to the actual image size
+    //! NOTE: this might be slow, for performance get the raw pointer and work on that!
+    glm::vec4 getTexel( glm::uvec2 _texCoord );
+
+    //! sets one texel, if the texture has less color components than 4, the superfluous components get ignored.
+    //! in case the texture is int, the values from 0..1 will get scaled and clamped if needed.
+    void setTexel( glm::uvec2 _texCoord, glm::vec4 _color );
     // ========================================================================================================= \/
     // ================================================================================================= SETTERS \/
     // ========================================================================================================= \/

src/ACGL/OpenGL/Data/TextureData.cc

@@ -49,3 +49,185 @@ size_t TextureData::getBytesPerScanline() const
     return width*getNumberOfChannels()*getGLTypeSize(mType) + paddingBytesPerRow;
 }
 
+
+glm::vec4 TextureData::getTexel( glm::uvec2 _texCoord )
+{
+    // clamp negative to 0:
+    _texCoord.x = std::max( 0u, _texCoord.x );
+    _texCoord.y = std::max( 0u, _texCoord.y );
+
+    // clamp values larger than the texture size to the maximum:
+    _texCoord.x = std::min( 0, getWidth()  );
+    _texCoord.y = std::min( 0, getHeight() );
+
+    // the byte offset into pData of the desired texel:
+    size_t texelOffset  = _texCoord.y * getBytesPerScanline();
+    texelOffset        += _texCoord.x * getNumberOfChannels()*getGLTypeSize(mType);
+
+    // default values:
+    glm::vec4 result = glm::vec4(0.0f, 0.0f, 0.0f, 1.0f);
+
+    if ( mType == GL_BYTE ) {
+        GLbyte *data = (GLbyte *) (pData+texelOffset);
+        result.r = data[0]/128.0f; // to -1..1
+        if ( getNumberOfChannels() > 1 ) result.g = data[1]/128.0f;
+        if ( getNumberOfChannels() > 2 ) result.b = data[2]/128.0f;
+        if ( getNumberOfChannels() > 3 ) result.a = data[3]/128.0f;
+
+    } else if ( mType == GL_UNSIGNED_BYTE ) {
+        GLshort *data = (GLshort *) (pData+texelOffset);
+        result.r = data[0]/255.0f; // to 0..1
+        if ( getNumberOfChannels() > 1 ) result.g = data[1]/255.0f;
+        if ( getNumberOfChannels() > 2 ) result.b = data[2]/255.0f;
+        if ( getNumberOfChannels() > 3 ) result.a = data[3]/255.0f;
+
+    } else if ( mType == GL_SHORT ) {
+        GLubyte *data = (GLubyte *) (pData+texelOffset);
+        result.r = data[0]/32768.0f; // to -1..1
+        if ( getNumberOfChannels() > 1 ) result.g = data[1]/32768.0f;
+        if ( getNumberOfChannels() > 2 ) result.b = data[2]/32768.0f;
+        if ( getNumberOfChannels() > 3 ) result.a = data[3]/32768.0f;
+
+    } else if ( mType == GL_UNSIGNED_SHORT ) {
+        GLushort *data = (GLushort *) (pData+texelOffset);
+        result.r = data[0]/65535.0f; // to 0..1
+        if ( getNumberOfChannels() > 1 ) result.g = data[1]/65535.0f;
+        if ( getNumberOfChannels() > 2 ) result.b = data[2]/65535.0f;
+        if ( getNumberOfChannels() > 3 ) result.a = data[3]/65535.0f;
+
+    } else if ( mType == GL_INT ) {
+        GLint *data = (GLint *) (pData+texelOffset);
+        result.r = data[0]/2147483648.0f; // to -1..1
+        if ( getNumberOfChannels() > 1 ) result.g = data[1]/2147483648.0f;
+        if ( getNumberOfChannels() > 2 ) result.b = data[2]/2147483648.0f;
+        if ( getNumberOfChannels() > 3 ) result.a = data[3]/2147483648.0f;
+
+    } else if ( mType == GL_UNSIGNED_INT ) {
+        GLuint *data = (GLuint *) (pData+texelOffset);
+        result.r = data[0]/4294967295.0f; // to 0..1
+        if ( getNumberOfChannels() > 1 ) result.g = data[1]/4294967295.0f;
+        if ( getNumberOfChannels() > 2 ) result.b = data[2]/4294967295.0f;
+        if ( getNumberOfChannels() > 3 ) result.a = data[3]/4294967295.0f;
+
+    } else if ( mType == GL_FLOAT ) {
+        GLfloat *data = (GLfloat *) (pData+texelOffset);
+        result.r = data[0];
+        if ( getNumberOfChannels() > 1 ) result.g = data[1];
+        if ( getNumberOfChannels() > 2 ) result.b = data[2];
+        if ( getNumberOfChannels() > 3 ) result.a = data[3];
+
+    } else if ( mType == GL_DOUBLE ) {
+        GLdouble *data = (GLdouble *) (pData+texelOffset);
+        result.r = (float) data[0];
+        if ( getNumberOfChannels() > 1 ) result.g = (float) data[1];
+        if ( getNumberOfChannels() > 2 ) result.b = (float) data[2];
+        if ( getNumberOfChannels() > 3 ) result.a = (float) data[3];
+
+    } else {
+        ACGL::Utils::error() << "datatype " << mType << " not supported for getTexel! Return (0,0,0,1)." << std::endl;
+    }
+
+    return result;
+}
+
+void TextureData::setTexel( glm::uvec2 _texCoord, glm::vec4 _color )
+{
+    // clamp negative to 0:
+    _texCoord.x = std::max( 0u, _texCoord.x );
+    _texCoord.y = std::max( 0u, _texCoord.y );
+
+    // clamp values larger than the texture size to the maximum:
+    _texCoord.x = std::min( 0, getWidth()  );
+    _texCoord.y = std::min( 0, getHeight() );
+
+    // the byte offset into pData of the desired texel:
+    size_t texelOffset  = _texCoord.y * getBytesPerScanline();
+    texelOffset        += _texCoord.x * getNumberOfChannels()*getGLTypeSize(mType);
+
+    if ( mType == GL_BYTE ) {
+        GLbyte *data = (GLbyte *) (pData+texelOffset);
+
+        glm::ivec4 color = glm::ivec4( _color * glm::vec4(128.0f) );
+        color = glm::clamp( color, glm::ivec4(-128), glm::ivec4(127) );
+
+        data[0] = color.r;
+        if ( getNumberOfChannels() > 1 ) data[1] = color.g;
+        if ( getNumberOfChannels() > 2 ) data[2] = color.b;
+        if ( getNumberOfChannels() > 3 ) data[3] = color.a;
+
+    } else if ( mType == GL_UNSIGNED_BYTE ) {
+        GLshort *data = (GLshort *) (pData+texelOffset);
+
+        glm::ivec4 color = glm::ivec4( _color * glm::vec4(255.0f) );
+        color = glm::clamp( color, glm::ivec4(0), glm::ivec4(255) );
+
+        data[0] = color.r;
+        if ( getNumberOfChannels() > 1 ) data[1] = color.g;
+        if ( getNumberOfChannels() > 2 ) data[2] = color.b;
+        if ( getNumberOfChannels() > 3 ) data[3] = color.a;
+
+    } else if ( mType == GL_SHORT ) {
+        GLubyte *data = (GLubyte *) (pData+texelOffset);
+
+        glm::ivec4 color = glm::ivec4( _color * glm::vec4(32768.0f) );
+        color = glm::clamp( color, glm::ivec4(-32768), glm::ivec4(32767) );
+
+        data[0] = color.r;
+        if ( getNumberOfChannels() > 1 ) data[1] = color.g;
+        if ( getNumberOfChannels() > 2 ) data[2] = color.b;
+        if ( getNumberOfChannels() > 3 ) data[3] = color.a;
+
+    } else if ( mType == GL_UNSIGNED_SHORT ) {
+        GLushort *data = (GLushort *) (pData+texelOffset);
+
+        glm::ivec4 color = glm::ivec4( _color * glm::vec4(65535.0f) );
+        color = glm::clamp( color, glm::ivec4(0), glm::ivec4(65535) );
+
+        data[0] = color.r;
+        if ( getNumberOfChannels() > 1 ) data[1] = color.g;
+        if ( getNumberOfChannels() > 2 ) data[2] = color.b;
+        if ( getNumberOfChannels() > 3 ) data[3] = color.a;
+
+    } else if ( mType == GL_INT ) {
+        GLint *data = (GLint *) (pData+texelOffset);
+
+        glm::ivec4 color = glm::ivec4( _color * glm::vec4(2147483648.0f) );
+        color = glm::clamp( color, glm::ivec4(-2147483648), glm::ivec4(2147483647) );
+
+        data[0] = color.r;
+        if ( getNumberOfChannels() > 1 ) data[1] = color.g;
+        if ( getNumberOfChannels() > 2 ) data[2] = color.b;
+        if ( getNumberOfChannels() > 3 ) data[3] = color.a;
+
+    } else if ( mType == GL_UNSIGNED_INT ) {
+        GLuint *data = (GLuint *) (pData+texelOffset);
+
+        glm::ivec4 color = glm::ivec4( _color * glm::vec4(4294967295.0f) );
+        color = glm::clamp( color, glm::ivec4(0), glm::ivec4(4294967295) );
+
+        data[0] = color.r;
+        if ( getNumberOfChannels() > 1 ) data[1] = color.g;
+        if ( getNumberOfChannels() > 2 ) data[2] = color.b;
+        if ( getNumberOfChannels() > 3 ) data[3] = color.a;
+
+    } else if ( mType == GL_FLOAT ) {
+        GLfloat *data = (GLfloat *) (pData+texelOffset);
+
+        data[0] = _color.r;
+        if ( getNumberOfChannels() > 1 ) data[1] = _color.g;
+        if ( getNumberOfChannels() > 2 ) data[2] = _color.b;
+        if ( getNumberOfChannels() > 3 ) data[3] = _color.a;
+
+    } else if ( mType == GL_DOUBLE ) {
+        GLdouble *data = (GLdouble *) (pData+texelOffset);
+
+        data[0] = (float) _color.r;
+        if ( getNumberOfChannels() > 1 ) data[1] = (float) _color.g;
+        if ( getNumberOfChannels() > 2 ) data[2] = (float) _color.b;
+        if ( getNumberOfChannels() > 3 ) data[3] = (float) _color.a;
+
+    } else {
+        ACGL::Utils::error() << "datatype " << mType << " not supported for setTexel!" << std::endl;
+    }
+}
+