| 1. |
- Akenine-Möller, Tomas, et al.
(författare)
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Graphics for the Masses: A Hardware Rasterization Architecture for Mobile Phones
- 2003
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Ingår i: ACM Transactions on Graphics. - : Association for Computing Machinery (ACM). - 1557-7368 .- 0730-0301. ; 22:3, s. 801-808
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Konferensbidrag (refereegranskat)abstract
- The mobile phone is one of the most widespread devices with rendering capabilities. Those capabilities have been very limited because the resources on such devices are extremely scarce; small amounts of memory, little bandwidth, little chip area dedicated for special purposes, and limited power consumption. The small display resolutions present a further challenge; the angle subtended by a pixel is relatively large, and therefore reasonably high quality rendering is needed to generate high fidelity images.To increase the mobile rendering capabilities, we propose a new hardware architecture for rasterizing textured triangles. Our architecture focuses on saving memory bandwidth, since an external memory access typically is one of the most energy-consuming operations, and because mobile phones need to use as little power as possible. Therefore, our system includes three new key innovations: 1) an inexpensive multisampling scheme that gives relatively high quality at the same cost of previous inexpensive schemes, II) a texture minification system, including texture compression, which gives quality relatively close to trilinear mipmapping at the cost of 1.33 32-bit memory accesses on average, III) a scanline-based culling scheme that avoids a significant amount of z-buffer reads, and that only requires one context. Software simulations show that these three innovations together significantly reduce the memory bandwidth. and thus also the power consumption.
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| 2. |
- Alexanderson, Simon, et al.
(författare)
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Listen, Denoise, Action! Audio-Driven Motion Synthesis with Diffusion Models
- 2023
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Ingår i: ACM Transactions on Graphics. - : Association for Computing Machinery (ACM). - 0730-0301 .- 1557-7368. ; 42:4
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Tidskriftsartikel (refereegranskat)abstract
- Diffusion models have experienced a surge of interest as highly expressive yet efficiently trainable probabilistic models. We show that these models are an excellent fit for synthesising human motion that co-occurs with audio, e.g., dancing and co-speech gesticulation, since motion is complex and highly ambiguous given audio, calling for a probabilistic description. Specifically, we adapt the DiffWave architecture to model 3D pose sequences, putting Conformers in place of dilated convolutions for improved modelling power. We also demonstrate control over motion style, using classifier-free guidance to adjust the strength of the stylistic expression. Experiments on gesture and dance generation confirm that the proposed method achieves top-of-the-line motion quality, with distinctive styles whose expression can be made more or less pronounced. We also synthesise path-driven locomotion using the same model architecture. Finally, we generalise the guidance procedure to obtain product-of-expert ensembles of diffusion models and demonstrate how these may be used for, e.g., style interpolation, a contribution we believe is of independent interest.
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| 3. |
- Andersson, Magnus, et al.
(författare)
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Masked Depth Culling for Graphics Hardware
- 2015
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Ingår i: Proceedings of ACM SIGGRAPH Asia 2015. - : Association for Computing Machinery (ACM). - 0730-0301. ; 34:6
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Konferensbidrag (refereegranskat)abstract
- Hierarchical depth culling is an important optimization, which is present in all modern high performance graphics processors. We present a novel culling algorithm based on a layered depth representation, with a per-sample mask indicating which layer each sample belongs to. Our algorithm is feed forward in nature in contrast to previous work, which rely on a delayed feedback loop. It is simple to implement and has fewer constraints than competing algorithms, which makes it easier to load-balance a hardware architecture. Compared to previous work our algorithm performs very well, and it will often reach over 90% of the efficiency of an optimal culling oracle. Furthermore, we can reduce bandwidth by up to 16% by compressing the hierarchical depth buffer.
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| 4. |
- Assarsson, Ulf, 1972, et al.
(författare)
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A Geometry-based Soft Shadow Volume Algorithm using Graphics Hardware
- 2003
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Ingår i: ACM Transactions on Graphics. - : Association for Computing Machinery (ACM). - 1557-7368 .- 0730-0301. ; 22:3, s. 511-520
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Konferensbidrag (refereegranskat)abstract
- Most previous soft shadow algorithms have either suffered from aliasing, been too slow, or could only use a limited set of shadow casters and/or receivers. Therefore, we present a strengthened soft shadow volume algorithm that deals with these problems. Our critical improvements include robust penumbra wedge construction, geometry-based visibility computation, and also simplified computation through a four-dimensional texture lookup. This enables us to implement the algorithm using programmable graphics hardware, and it results in images that most often are indistinguishable from images created as the average of 1024 hard shadow images. Furthermore, our algorithm can use both arbitrary shadow casters and receivers. Also, one version of our algorithm completely avoids sampling artifacts which is rare for soft shadow algorithms. As a bonus, the four-dimensional texture lookup allows for small textured light sources, and, even video textures can be used as light sources. Our algorithm has been implemented in pure software, and also using the GeForce FX emulator with pixel shaders. Our software implementation renders soft shadows at 0.5-5 frames per second for the images in this paper. With actual hardware, we expect that our algorithm will render soft shadows in real time. An important performance measure is bandwidth usage. For the same image quality, an algorithm using the accumulated hard shadow images uses almost two orders of magnitude more bandwidth than our algorithm.
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| 5. |
- Barringer, Rasmus, et al.
(författare)
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A(4): Asynchronous Adaptive Anti-Aliasing using Shared Memory
- 2013
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Ingår i: ACM Transactions on Graphics. - : Association for Computing Machinery (ACM). - 0730-0301 .- 1557-7368. ; 32:4, s. 100-100
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Tidskriftsartikel (refereegranskat)abstract
- Edge aliasing continues to be one of the most prominent problems in real-time graphics, e.g., in games. We present a novel algorithm that uses shared memory between the GPU and the CPU so that these two units can work in concert to solve the edge aliasing problem rapidly. Our system renders the scene as usual on the GPU with one sample per pixel. At the same time, our novel edge aliasing algorithm is executed asynchronously on the CPU. First, a sparse set of important pixels is created. This set may include pixels with geometric silhouette edges, discontinuities in the frame buffer, and pixels/polygons under user-guided artistic control. After that, the CPU runs our sparse rasterizer and fragment shader, which is parallel and SIMD:ified, and directly accesses shared resources (e.g., render targets created by the GPU). Our system can render a scene with shadow mapping with adaptive anti-aliasing with 1 6 samples per important pixel faster than the GPU with 8 samples per pixel using multi-sampling anti-aliasing. Since our system consists of an extensive code base, it will be released to the public for exploration and usage.
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| 6. |
- Barringer, Rasmus, et al.
(författare)
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Dynamic Ray Stream Traversal
- 2014
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Ingår i: ACM Transactions on Graphics. - : Association for Computing Machinery (ACM). - 0730-0301 .- 1557-7368. ; 33:4, s. 9-151
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Konferensbidrag (refereegranskat)abstract
- While each new generation of processors gets larger caches and more compute power, external memory bandwidth capabilities increase at a much lower pace. Additionally, processors are equipped with wide vector units that require low instruction level divergence to be efficiently utilized. In order to exploit these trends in ray tracing, we present an alternative to traditional depth-first ray traversal that takes advantage of the available cache hierarchy, and provides high SIMD efficiency, while keeping memory bus traffic low. Our main contribution is an efficient algorithm for traversing large packets of rays against a bounding volume hierarchy in a way that groups coherent rays during traversal. In contrast to previous large packet traversal methods, our algorithm allows for individual traversal order for each ray, which is essential for efficient ray tracing. Ray tracing algorithms is a mature research field in computer graphics, and despite this, our new technique increases traversal performance by 36-53%, and is applicable to most ray tracers.
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| 7. |
- Barringer, Rasmus, et al.
(författare)
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High-Quality Curve Rendering using Line Sampled Visibility
- 2012
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Ingår i: ACM Transactions on Graphics. - : Association for Computing Machinery (ACM). - 0730-0301 .- 1557-7368. ; 31:6, s. 162-162
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Tidskriftsartikel (refereegranskat)abstract
- Computing accurate visibility for thin primitives, such as hair strands, fur, grass, at all scales remains difficult or expensive. To that end, we present an efficient visibility algorithm based on spatial line sampling, and a novel intersection algorithm between line sample planes and Bezier splines with varying thickness. Our algorithm produces accurate visibility both when the projected width of the curve is a tiny fraction of a pixel, and when the projected width is tens of pixels. In addition, we present a rapid resolve procedure that computes final visibility. Using an optimized implementation running on graphics processors, we can render tens of thousands long hair strands with noise-free visibility at near-interactive rates.
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| 8. |
- Cheslack-Postava, E., et al.
(författare)
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Fast, realistic lighting and material design using nonlinear cut approximation
- 2008
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Ingår i: ACM Transactions on Graphics. - : Association for Computing Machinery (ACM). - 0730-0301 .- 1557-7368. ; 27:5
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Tidskriftsartikel (refereegranskat)abstract
- We present an efficient computational algorithm for functions represented by a nonlinear piecewise constant approximation called cuts. Our main contribution is a single traversal algorithm for merging cuts that allows for arbitrary pointwise computation, such as addition, multiplication, linear interpolation, and multi-product integration. A theoretical error bound of this approach can be proved using a statistical interpretation of cuts. Our algorithm extends naturally to computation with many cuts and maps easily to modern GPUs, leading to significant advantages over existing methods based on wavelet approximation. We apply this technique to the problem of realistic lighting and material design under complex illumination with arbitrary BRDFs. Our system smoothly integrates all-frequency relighting of shadows and reflections with dynamic per-pixel shading effects, such as bump mapping and spatially varying BRDFs. This combination of capabilities is typically missing in current systems. We represent illumination and precomputed visibility as nonlinear sparse vectors, we then use our cut merging algorithm to simultaneously interpolate visibility cuts at each pixel, and compute the triple product integral of the illumination, interpolated visibility, and dynamic BRDF samples. Finally, we present a two-pass, data-driven approach that exploits pilot visibility samples to optimize the construction of the light tree, leading to more efficient cuts and reduced datasets. © 2008 ACM.
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| 9. |
- Clarberg, Petrik, et al.
(författare)
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AMFS: Adaptive Multi-Frequency Shading for Future Graphics Processors
- 2014
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Ingår i: ACM Transactions on Graphics. - : Association for Computing Machinery (ACM). - 0730-0301 .- 1557-7368. ; 33:4, s. 141-141
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Tidskriftsartikel (refereegranskat)abstract
- We propose a powerful hardware architecture for pixel shading, which enables flexible control of shading rates and automatic shading reuse between triangles in tessellated primitives. The main goal is efficient pixel shading for moderately to finely tessellated geometry, which is not handled well by current GPUs. Our method effectively decouples the cost of pixel shading from the geometric complexity. It thereby enables a wider use of tessellation and fine geometry, even at very limited power budgets. The core idea is to shade over small local grids in parametric patch space, and reuse shading for nearby samples. We also support the decomposition of shaders into multiple parts, which are shaded at different frequencies. Shading rates can be locally and adaptively controlled, in order to direct the computations to visually important areas and to provide performance scaling with a graceful degradation of quality. Another important benefit of shading in patch space is that it allows efficient rendering of distribution effects, which further closes the gap between real-time and offline rendering.
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| 10. |
- Clarberg, Petrik, et al.
(författare)
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Wavelet Importance Sampling: Efficiently Evaluating Products of Complex Functions
- 2005
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Ingår i: ACM Transactions on Graphics. - : Association for Computing Machinery (ACM). - 0730-0301 .- 1557-7368. ; 24:3, s. 1166-1175
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Konferensbidrag (refereegranskat)abstract
- We present a new technique for importance sampling products of complex functions using wavelets. First, we generalize previous work on wavelet products to higher dimensional spaces and show how this product can be sampled on-the-fly without the need of evaluating the full product. This makes it possible to sample products of high-dimensional functions even if the product of the two functions in itself is too memory consuming. Then, we present a novel hierarchical sample warping algorithm that generates high-quality point distributions, which match the wavelet representation exactly. One application of the new sampling technique is rendering of objects with measured BRDFs illuminated by complex distant lighting - our results demonstrate how the new sampling technique is more than an order of magnitude more efficient than the best previous techniques. Copyright
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