Graphic rendering system and projection method thereof

摘要

A graphic rendering system and a projection method thereof are provided. The graphic rendering system comprises a processing unit and a storage unit. The storage unit stores a piece of information. The information defines a virtual area in a camera space, wherein the virtual area has three vertices. The processing unit calculates two intersection vertices between the virtual area and near clipping plane of a view volume of the camera space. The processing unit transforms the three vertices and the two intersection vertices to a screen space and derives three projection vertices and two projection intersection vertices. The processing unit decides a valid area, chooses a test vertex from the valid area, and decides whether the signs of the three projection edge functions defined by the three projection vertices should be changed. Then, the processing unit decides pixels to be rendered according to the valid area, projection edge functions, and a predefined window clipping region.

主权项

1. A graphic rendering system, comprising:
a storage unit, being stored with a piece of information, the piece of information defining a virtual area in a camera space, the virtual area having a first vertex, a second vertex, and a third vertex; and a processing unit, for determining that the first vertex and the second vertex are inside a view volume of the camera space and the third vertex is outside the view volume, the processing unit calculating a first intersection vertex of a first edge function and a near clipping plane of the view volume, the first edge function being formed by the first vertex and the third vertex, the processing unit calculating a second intersection vertex of a second edge function and the near clipping plane, the second edge function being formed by the second vertex and the third vertex, the processing unit respectively transforming the first vertex, the second vertex, the third vertex, the first intersection vertex, and the second intersection vertex to a screen space to derive a first projection vertex, a second projection vertex, a third projection vertex, a first projection intersection vertex, and a second projection intersection vertex, wherein the first projection vertex, the second projection vertex, the first projection intersection vertex, and the second projection intersection vertex form a valid area, the second projection vertex and the third projection vertex define a first projection edge function in the screen space, the first projection vertex and the third projection vertex define a second projection edge function in the screen space, the first projection vertex and the second projection vertex define a third projection edge function in the screen space, the processing unit chooses a test vertex from the valid area, and the processing unit determines that the third projection edge function should be multiplied by a minus sign according to the test vertex.