Transformation Transformation of of Rendering Algorithms Rendering Algorithms for Hardware for Hardware Implementation Implementation Ph.D. Thesis by: Ph.D. Thesis by: Ali Mohamed Ali Abbas Ali Mohamed Ali Abbas Scientific Supervisor: Scientific Supervisor: Professor Dr. Szirmay-Kalos László Professor Dr. Szirmay-Kalos László Department of Control Engineering and Department of Control Engineering and Information Technology Information Technology Faculty of Electrical Engineering and Faculty of Electrical Engineering and Informatics Informatics Budapest University of Technology and Budapest University of Technology and Economics Economics
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Transformation of Rendering Algorithms for Hardware Implementation
Transformation of Rendering Algorithms for Hardware Implementation. Ph.D. Thesis by: Ali Mohamed Ali Abbas Scientific Supervisor: Professor Dr. Szirmay-Kalos László Department of Control Engineering and Information Technology Faculty of Electrical Engineering and Informatics - PowerPoint PPT Presentation
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Transformation Transformation of of Rendering AlgorithmsRendering Algorithms
for Hardware Implementationfor Hardware ImplementationPh.D. Thesis by:Ph.D. Thesis by:
Ali Mohamed Ali AbbasAli Mohamed Ali Abbas
Scientific Supervisor: Scientific Supervisor: Professor Dr. Szirmay-Kalos LászlóProfessor Dr. Szirmay-Kalos László
Department of Control Engineering and Information TechnologyDepartment of Control Engineering and Information TechnologyFaculty of Electrical Engineering and InformaticsFaculty of Electrical Engineering and Informatics
Budapest University of Technology and EconomicsBudapest University of Technology and Economics
Budapest, 200Budapest, 20033..
The outlines of this talkThe outlines of this talk
General rendering schemes. Problems of current rendering approaches:
- low quality, simple, hardware supported. - high quality, complex, not hardware supported.
The main aim of this thesis is to convert high quality complex algorithms to make them appropriate for hardware realization.
The proposed solutionsThe proposed solutions
- general framework (Thesis 1)- filtered line drawing (Thesis 2)- spherical interpolation for Phong shading (Thesis 3)- quadratic interpolation for Phong shading and texturing (Thesis 4)- hardware support for global illumination (Thesis 5)
Incremental renderingIncremental rendering
x
y
z
• Gouraud shading.• Phong shading.
N
LV
Gouraud shadingGouraud shading
Diffuse
X
Y
R,G,BR(X,Y) = a X + bY + c
R(X,Y)
R(X+1,Y) = R(X,Y)
Specular
+a
Ambient
System outline of Gouraud shaderSystem outline of Gouraud shader
The accuracy of the fixed-point representation was investigated, and the number of fractional bits was computed
General framework (Thesis 1)General framework (Thesis 1)
Incremental concept for Incremental concept for quadratic and linear functionsquadratic and linear functions
I(X,Y) = T5 X 2 +T4 X Y +T3 Y 2 +T2 X+T1Y+T0 .
I(X+1,Y) = I(X,Y) (2T5 X + T4 Y +T5 +T2 ) .
I (X,Y)
+
+
I (X +1,Y) = I (X,Y) 2T5 .
PublicationsPublications1. A. M. Abbas. “Photorealistic Images in Real-Time”, No 20, 2003, in the Journal of “Industrial Researches’’.
2. A. M. Abbas, L. Szirmay-Kalos, and T. Horváth. “Hardware Implementation of Phong Shading using Spherical Interpolation”. “Periodica Polytechnica”, 44(3-4): 283-301, 2000.
3. A. M. Abbas, L. Szirmay-Kalos, T. Horváth, and T. Fóris. “Quadratic Shading and its Hardware Interpolation”, “Machine GRAPHICS & VISION “, 9(4):625-839, 2000.
4. A. M. Abbas, L. Szirmay-Kalos, T. Horváth, T. Fóris, and G. Szijártó, “Quadratic Interpolation in Hardware Rendering”, In “Spring Conference on Computer Graphics”, Budmerice, Slovakia, April 2001. (Best paper award).
Filtered Line Drawing (Thesis 2)Filtered Line Drawing (Thesis 2)
Bresenham’s
Box-filtering
Incremental cone-filtering
(Stair-like jaggies)
Cone filtering of linesCone filtering of lines
(ΔX)2 + (ΔY) 2
ΔXD = d . cos Φ =
DH = (1 - d) . cos Φ = - D + ΔD
DL = (1 + d) . cos Φ = D + ΔD
D(X+1) = D(X) +
D(X+1) = - D(X) + (ΔX)2 + (ΔY) 2
= - D(X) + ΔD+
ΔX - ΔY = D(X) + ΔD-
= d . ΔD
d .
ΔY
(ΔX)2 + (ΔY) 2
Block scheme of incremental cone-filteringBlock scheme of incremental cone-filtering
Publications:1. A. M. Abbas. “On 2D Line Scan Conversion”.In “Conference on The Latest Results in Information Technology”. IIT, Technical University of Budapest, Hungary, 1998.
2. A. M. Abbas. “Photorealistic Images in Real-Time”. No 20, 2003, in the Journal of “Industrial Researches’’.
Evaluation of the visual accuracy of the functions cosn x cos2 ax
6 bits4 bits
Quantization errors of address/data bits by cos2 ax
6 bits4 bits
cos2 ax cos2 ax
cos2 axcos2 ax
cos2 x cos2 x
Block scheme of spherical interpolationBlock scheme of spherical interpolation
Publications:1. A. M. Abbas, L. Szirmay-Kalos, and T. Horváth. “Hardware Implementation of Phong Shading using Spherical Interpolation”. “Periodica Polytechnica”, 44(3-4):283--301, 2000.
Quadratic interpolation Quadratic interpolation The interpolation is done in image space. The interpolation is not linear, but rather quadratic. Quadratic form has 6 degrees of freedom.
2. A. M. Abbas, L. Szirmay-Kalos, T. Horváth, T. Fóris, and G. Szijártó.
“Quadratic Interpolation in Hardware Rendering”.
In “Spring Conference on Computer Graphics”,
Budmerice, Slovakia, April 2001, (Best paper award).
3. A. M. Abbas, L. Szirmay-Kalos, T. Horváth, T. Fóris, and G. Szijártó.
“Quadratic Interpolation in Hardware Phong Shading and Texture Mapping”.
In “IEEE Computer Society Press in the Post-Proceedings of The 17 th.
Spring Conference on Computer Graphics”, Budmerice, Slovakia, April 2001.
Hardware support for Hardware support for global illumination (Thesis 5)global illumination (Thesis 5)
Local illumination Local illumination + ambient term
Global illumination
Radiance transfer by transillumination bufferRadiance transfer by transillumination buffer
Transillumination image buffer
Random, global direction
1
2
3
3
1 3
1 2 3
2
- identifying the patches that are visible from a given patch- solution of global visibility problem, transillumination direction - store in visibility map, extended (or modified ) z-buffer
Block scheme of global illuminationBlock scheme of global illumination
Publications: 1. L. Kovács, L. Szirmay-Kalos, and A. M. Abbas. “Testing Global Illumination Methods with Analytically Computable Scenes”. In “Winter School of Computer Graphics”, II:419--426, Plzen, Cz., February 2001. 2. R. Martinez, L. Szirmay-Kalos, M. Sbert, and A. M. Abbas. “Parallel implementation of Stochastic Iteration Algorithms”. In “Winter School of Computer Graphics”, II:344--351, Plzen, Cz., February 2001.
Thesis 1: - general methodology based on incremental concept.
Thesis 2:- anti-aliased line drawing algorithm with simple operations
Thesis 3:- single cosine function (reduced number of dot-products) - no normalization or scalar exponentiation are required
Thesis 4:- approximates non-linear functions (Phong shading or texturing). - simple for hardware implementation. - arbitrary BRDF models.- independent of the number of light sources.
Thesis 5:- speedup global illumination.
SummarySummary
Simulation environments:– the proposed algorithms first simulated in software using C++,
then transformed to hardware design, specified in VHDL and simulated in Model-Technology environments assuming the delay times of a real FPGA device.
– the results demonstrate that, these hardware schemes could provide
appropriate pixel drawing time, enough for real-time rendering
These hardware schemes have not been build yet
Possible applications of the results:– Development of new hardware,
– Efficient CPU level and vertex/pixel shader level program development.