README.md

GLSL-Pie-Transition-Shaders

OpenGL Shaders For Transition Effect Between RECT(W,H,StartX,RangeX) to PIE(X,Y,R,Angle)

Example Usage EnPie Shader

It translates Rectangle texture space to Pie space

void draw(float l, float t, float r, float b, int texture, float zoomStartX, float zoomRangeX, float pieX, float pieY, float pieRadius, float power, float angle, FloatBuffer buffer, float[] matrix) {
		glUseProgram(shader.program);

		glUniformMatrix3fv(uViewMatrix, 1, false, matrix, 0);
		glUniform2f(uOffset, l, t);

		float width = r - l;
		glUniform2f(uSize, width, b - t);

		float zoomStart = (zoomStartX - l) / width;
		float zoomRange = zoomRangeX / width;
		zoomStart = zoomStart * power;
		zoomRange = (1.f - zoomRange) * (1.f - power) + zoomRange;
		glUniform2f(uZoom, zoomStart, zoomRange);
		glUniform2f(uCenter, pieX - l, pieY - t);
		glUniform1f(uRadius, pieRadius);
		glUniform1f(uPower, power);
		glUniform1f(uAngle, angle);

		glActiveTexture(GL_TEXTURE0);
		glBindTexture(GL_TEXTURE_2D, texture);
		glUniform1i(uTexture, 0);

		glEnableVertexAttribArray(aVertex);
		glVertexAttribPointer(aVertex, 2, GL_FLOAT, false, 0, buffer);
		glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);

		glBindTexture(GL_TEXTURE_2D, GL_NONE);
		glDisableVertexAttribArray(aVertex);
		glUseProgram(0);
}

Example Usage DePie Shader

It translates Pie texture space to Rectangle space

void draw(float l, float t, float r, float b, int texture, float zoomStartX, float zoomRangeX, float pieX, float pieY, float pieRadius, float power, float angle, FloatBuffer buffer, float[] matrix) {
		glUseProgram(shader.program);

		glUniformMatrix3fv(uViewMatrix, 1, false, matrix, 0);
		glUniform2f(uOffset, l, t);

		float width = r - l;
		glUniform2f(uSize, width, b - t);

		float zoomStart = (zoomStartX - l) / width;
		float zoomRange = zoomRangeX / width;
		float enZoomStart = zoomStart * power;
		float enZoomRange = (1.f - zoomRange) * (1.f - power) + zoomRange;

		float x1 = (zoomStart - enZoomStart) / enZoomRange;
		float x2 = ((zoomStart + zoomRange) - enZoomStart) / enZoomRange;

		glUniform2f(uZoom, x1, x2);
		glUniform2f(uCenter, pieX - l, pieY - t);
		glUniform1f(uRadius, pieRadius);
		glUniform1f(uPower, power);
		glUniform1f(uAngle, angle);

		glActiveTexture(GL_TEXTURE0);
		glBindTexture(GL_TEXTURE_2D, texture);
		glUniform1i(uTexture, 0);

		glEnableVertexAttribArray(aVertex);
		glVertexAttribPointer(aVertex, 2, GL_FLOAT, false, 0, buffer);
		glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);

		glBindTexture(GL_TEXTURE_2D, GL_NONE);
		glDisableVertexAttribArray(aVertex);
		glUseProgram(0);
}