Dudnyk O. Methods and tools of increasing the realism and productivity of texture mapping in computer graphics systems

In the thesis the theory of rendering of three-dimensional scenes was supplemented, which allowed to solve the problem of improving the performance of image formation and their realism in computer graphics systems using new methods and tools for texture overlay, filtering and simulation of surface irregularities. The author proposes a method of anisotropic filtering with use the weight functions based on the Gauss pixel model taking into account the shape of the pixel projection in the texture plane, which makes it possible to improve the accuracy of the pixel color. This gave the opportunity to increase the accuracy of determining the color of pixels. The author proposes new formulas for calculating the volume of cutting off the body of rotation of the Gauss curve for use in the process of performing anisotropic texture filtering with subtextual accuracy. This makes it possible to increase the realism of anisotropic texture filtering by taking into account the physical properties of the pixel. For the first time author proposes the use of special texture maps to determine the weight coefficients of texels when performing anisotropic texture filtering instead of calculating them in real time in order to extract complex calculations from the computational process and improve the productivity of the texturing process. The use of weight maps made it possible to increase productivity by 25%. The author proposes a modification of the Heckbert method, which uses iterative formulas to calculate the coordinates of texels, which allowed to reduce the number of addition and multiplication operations to determine the texture coordinates of the pixel, and as a consequence, to increase productivity by 26%. New iterative formulas for determining the parameters of the ellipse equation for calculating the position of the pixel projection on the texture plane using the Heckbert method are proposed. Their use allows to reduce the number of arithmetic operations in the computing process and increase productivity by 18%. For the first time author proposes a method of texture mapping, the peculiarity of which is to perform procedural operations in the object space and filtering in the screen plane, which makes it possible to eliminate artifacts characteristic of the methods of texturing in the screen plane and increase the realism of image formation. To implement the method, the author has developed a new rendering pipeline by combining a set of computational and graphic shaders. Improving the performance of the rendering of the proposed facilities in relation to rendering using anisotropic texture filtering is on average 30%. The author proposed a modified parallax mapping method using a distance map to a surface that differs from the classical use of a modified distance map that takes into account the visibility of texels, and allows to increase the productivity of relief texturing up to 11%. The author has found the causes of visualization errors when using parallax mapping technology in combination with anisotropic texture filtering and proposed a combined method of relief texturing using parallax mapping technology and anisotropic filtering. The method allowed to eliminate artifacts characteristic of images formed by combining these technologies by checking texels, which form the projection of the pixel visibility. On the basis of the theoretical propositions, models, analytical dependences, results of the experimental analysis obtained in the thesis, the author proposes algorithms and software tools for texture mapping in the systems of highly realistic rendering of three-dimensional images.