Interpolating sample values from known triangle vertex values

A graphics system comprising:

• an input configured to receive graphics data including three vertices defining a triangle;
• and
• a rendering unit coupled to the input and configured to receive the graphics data including the three vertices defining the triangle from the input unit, wherein the rendering unit is further configured to generate samples in a two-dimensional screen space, wherein the rendering unit is configured to determine which of said samples reside inside the triangle;
• wherein said rendering unit is configured to compute a first axial rate of change of a first ordinate based on the three vertices, and, for each sample residing inside the triangle, (a) to multiply the first axial rate by a first sample displacement resulting in a first product, (b) to interpolate a first projection value for a projection point on a first edge of the triangle, and (c) to add the first product to the first projection value resulting in a first sample ordinate value, wherein the first sample ordinate value is usable to determine at least a portion of a displayable image.

A method for computing sample ordinate values in a graphics system, the method comprising:

• receiving graphics data including three vertices defining a triangle;
• receiving sample positions which reside in a two-dimensional screen space;
• computing a first axial rate of change of a first ordinate based on the three vertices, and, for each of said sample positions residing inside the triangle:
• (a) multiplying the first axial rate by a first sample displacement resulting in a first product;
• (b) interpolating a first projection value for a projection point on a first edge of the triangle;
• and
• (c) adding the first product to the first projection value resulting in a first sample ordinate value, wherein said first sample ordinate value is usable to determine at least a portion of a displayable image.

A method comprising:

• receiving graphics data including three vertices defining a triangle;
• receiving samples which reside in a two-dimensional screen space;
• computing a first minor axis ordinate difference along a minor axis of the triangle;
• and
• computing a first sample ordinate value for each sample inside the triangle, wherein said computing the first sample ordinate value for a first sample inside the triangle includes:
• (a) computing a minor axis positional fraction corresponding to the first sample;
• (b) multiplying the minor axis positional fraction by the first minor axis ordinate difference to generate a first product;
• and
• (c) adding the first product to one or more ordinate adjustment values to generate the first sample ordinate value, wherein the first sample ordinate value is usable to determine at least a portion of a pixel in a displayable image.

A graphics system comprising:

• sample position generation logic configured to generate sample positions in a two-dimensional screen space;
• sample ordinate generation logic configured to receive graphics data including three vertices defining a triangle and ordinate data for each of the three vertices, and to compute a first minor axis ordinate difference along a minor axis of the triangle, wherein the rendering unit is further configured to compute a first sample ordinate value for a first sample position inside the triangle by:
• (a) computing a minor axis positional fraction corresponding to the first sample position;
• (b) multiplying the minor axis positional fraction by the first minor axis ordinate difference to generate a first product;
• (c) adding the first product to one or more ordinate adjustment values to generate the first sample ordinate value, wherein the first sample ordinate value is usable to determine at least a portion of a pixel in a displayable image.

A method for computing pixel ordinate values in a graphics system, the method comprising:

• receiving graphics data including three vertices defining a triangle;
• receiving pixel positions which reside in a two-dimensional screen space;
• computing a first axial rate of change of a first ordinate based on the three vertices, and, for each of said pixel positions residing inside the triangle:
• (a) multiplying the first axial rate by a first pixel displacement resulting in a first product;
• (b) interpolating a first projection value for a projection point on a first edge of the triangle;
• and
• (c) adding the first product to the first projection value resulting in a first pixel ordinate value, wherein said first pixel ordinate value is usable to determine at least a portion of a displayable image.