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Diffstat (limited to 'src/mesa/shader/slang/library/slang_vertex_builtin.gc')
-rwxr-xr-x | src/mesa/shader/slang/library/slang_vertex_builtin.gc | 262 |
1 files changed, 262 insertions, 0 deletions
diff --git a/src/mesa/shader/slang/library/slang_vertex_builtin.gc b/src/mesa/shader/slang/library/slang_vertex_builtin.gc new file mode 100755 index 00000000000..cb043623869 --- /dev/null +++ b/src/mesa/shader/slang/library/slang_vertex_builtin.gc @@ -0,0 +1,262 @@ + +// +// TODO: +// - what to do with ftransform? can it stay in the current form? +// - implement texture1DLod, texture2DLod, texture3DLod, textureCubeLod, +// - implement shadow1DLod, shadow2DLod, +// + +// +// From Shader Spec, ver. 1.10, rev. 59 +// +// Some OpenGL operations still continue to occur in fixed functionality in between the vertex +// processor and the fragment processor. Other OpenGL operations continue to occur in fixed +// functionality after the fragment processor. Shaders communicate with the fixed functionality +// of OpenGL through the use of built-in variables. +// +// The variable gl_Position is available only in the vertex language and is intended for writing +// the homogeneous vertex position. All executions of a well-formed vertex shader must write +// a value into this variable. It can be written at any time during shader execution. It may also +// be read back by the shader after being written. This value will be used by primitive assembly, +// clipping, culling, and other fixed functionality operations that operate on primitives after +// vertex processing has occurred. Compilers may generate a diagnostic message if they detect +// gl_Position is not written, or read before being written, but not all such cases are detectable. +// Results are undefined if a vertex shader is executed and does not write gl_Position. +// +// The variable gl_PointSize is available only in the vertex language and is intended for a vertex +// shader to write the size of the point to be rasterized. It is measured in pixels. +// +// The variable gl_ClipVertex is available only in the vertex language and provides a place for +// vertex shaders to write the coordinate to be used with the user clipping planes. The user must +// ensure the clip vertex and user clipping planes are defined in the same coordinate space. User +// clip planes work properly only under linear transform. It is undefined what happens under +// non-linear transform. +// +// These built-in vertex shader variables for communicating with fixed functionality are +// intrinsically declared with the following types: +// + +vec4 gl_Position; // must be written to +float gl_PointSize; // may be written to +vec4 gl_ClipVertex; // may be written to + +// +// If gl_PointSize or gl_ClipVertex are not written to, their values are undefined. Any of these +// variables can be read back by the shader after writing to them, to retrieve what was written. +// Reading them before writing them results in undefined behavior. If they are written more than +// once, it is the last value written that is consumed by the subsequent operations. +// +// These built-in variables have global scope. +// + +// +// The following attribute names are built into the OpenGL vertex language and can be used from +// within a vertex shader to access the current values of attributes declared by OpenGL. All page +// numbers and notations are references to the OpenGL 1.4 specification. +// + +// +// Vertex Attributes, p. 19. +// + +attribute vec4 gl_Color; +attribute vec4 gl_SecondaryColor; +attribute vec3 gl_Normal; +attribute vec4 gl_Vertex; +attribute vec4 gl_MultiTexCoord0; +attribute vec4 gl_MultiTexCoord1; +attribute vec4 gl_MultiTexCoord2; +attribute vec4 gl_MultiTexCoord3; +attribute vec4 gl_MultiTexCoord4; +attribute vec4 gl_MultiTexCoord5; +attribute vec4 gl_MultiTexCoord6; +attribute vec4 gl_MultiTexCoord7; +attribute float gl_FogCoord; + +// +// Unlike user-defined varying variables, the built-in varying variables don�t have a strict +// one-to-one correspondence between the vertex language and the fragment language. Two sets are +// provided, one for each language. Their relationship is described below. +// +// The following built-in varying variables are available to write to in a vertex shader. +// A particular one should be written to if any functionality in a corresponding fragment shader +// or fixed pipeline uses it or state derived from it. Otherwise, behavior is undefined. +// + +varying vec4 gl_FrontColor; +varying vec4 gl_BackColor; +varying vec4 gl_FrontSecondaryColor; +varying vec4 gl_BackSecondaryColor; +varying vec4 gl_TexCoord[]; // at most will be gl_MaxTextureCoords +varying float gl_FogFragCoord; + +// +// For gl_FogFragCoord, the value written will be used as the �c� value on page 160 of the +// OpenGL 1.4 Specification by the fixed functionality pipeline. For example, if the z-coordinate +// of the fragment in eye space is desired as �c�, then that's what the vertex shader should write +// into gl_FogFragCoord. +// +// As with all arrays, indices used to subscript gl_TexCoord must either be an integral constant +// expressions, or this array must be re-declared by the shader with a size. The size can be +// at most gl_MaxTextureCoords. Using indexes close to 0 may aid the implementation +// in preserving varying resources. +// + +// +// The OpenGL Shading Language defines an assortment of built-in convenience functions for scalar +// and vector operations. Many of these built-in functions can be used in more than one type +// of shader, but some are intended to provide a direct mapping to hardware and so are available +// only for a specific type of shader. +// +// The built-in functions basically fall into three categories: +// +// � They expose some necessary hardware functionality in a convenient way such as accessing +// a texture map. There is no way in the language for these functions to be emulated by a shader. +// +// � They represent a trivial operation (clamp, mix, etc.) that is very simple for the user +// to write, but they are very common and may have direct hardware support. It is a very hard +// problem for the compiler to map expressions to complex assembler instructions. +// +// � They represent an operation graphics hardware is likely to accelerate at some point. The +// trigonometry functions fall into this category. +// +// Many of the functions are similar to the same named ones in common C libraries, but they support +// vector input as well as the more traditional scalar input. +// +// Applications should be encouraged to use the built-in functions rather than do the equivalent +// computations in their own shader code since the built-in functions are assumed to be optimal +// (e.g., perhaps supported directly in hardware). +// +// User code can replace built-in functions with their own if they choose, by simply re-declaring +// and defining the same name and argument list. +// + +// +// Geometric Functions +// +// These operate on vectors as vectors, not component-wise. +// + +// +// For vertex shaders only. This function will ensure that the incoming vertex value will be +// transformed in a way that produces exactly the same result as would be produced by OpenGL�s +// fixed functionality transform. It is intended to be used to compute gl_Position, e.g., +// gl_Position = ftransform() +// This function should be used, for example, when an application is rendering the same geometry in +// separate passes, and one pass uses the fixed functionality path to render and another pass uses +// programmable shaders. +// + +vec4 ftransform () { + return gl_ModelViewProjectionMatrix * gl_Vertex; +} + +// +// 8.7 Texture Lookup Functions +// +// Texture lookup functions are available to both vertex and fragment shaders. However, level +// of detail is not computed by fixed functionality for vertex shaders, so there are some +// differences in operation between vertex and fragment texture lookups. The functions in the table +// below provide access to textures through samplers, as set up through the OpenGL API. Texture +// properties such as size, pixel format, number of dimensions, filtering method, number of mip-map +// levels, depth comparison, and so on are also defined by OpenGL API calls. Such properties are +// taken into account as the texture is accessed via the built-in functions defined below. +// +// If a non-shadow texture call is made to a sampler that represents a depth texture with depth +// comparisons turned on, then results are undefined. If a shadow texture call is made to a sampler +// that represents a depth texture with depth comparisions turned off, the results are undefined. +// If a shadow texture call is made to a sampler that does not represent a depth texture, then +// results are undefined. +// +// In all functions below, the bias parameter is optional for fragment shaders. The bias parameter +// is not accepted in a vertex shader. For a fragment shader, if bias is present, it is added to +// the calculated level of detail prior to performing the texture access operation. If the bias +// parameter is not provided, then the implementation automatically selects level of detail: +// For a texture that is not mip-mapped, the texture is used directly. If it is mip-mapped and +// running in a fragment shader, the LOD computed by the implementation is used to do the texture +// lookup. If it is mip-mapped and running on the vertex shader, then the base texture is used. +// +// The built-ins suffixed with �Lod� are allowed only in a vertex shader. For the �Lod� functions, +// lod is directly used as the level of detail. +// + +// +// Use the texture coordinate coord to do a texture lookup in the 1D texture currently bound +// to sampler. For the projective (�Proj�) versions, the texture coordinate coord.s is divided by +// the last component of coord. +// +// XXX +vec4 texture1DLod (sampler1D sampler, float coord, float lod) { + return vec4 (0.0); +} +vec4 texture1DProjLod (sampler1D sampler, vec2 coord, float lod) { + return texture1DLod (sampler, coord.s / coord.t, lod); +} +vec4 texture1DProjLod (sampler1D sampler, vec4 coord, float lod) { + return texture1DLod (sampler, coord.s / coord.q, lod); +} + +// +// Use the texture coordinate coord to do a texture lookup in the 2D texture currently bound +// to sampler. For the projective (�Proj�) versions, the texture coordinate (coord.s, coord.t) is +// divided by the last component of coord. The third component of coord is ignored for the vec4 +// coord variant. +// +// XXX +vec4 texture2DLod (sampler2D sampler, vec2 coord, float lod) { + return vec4 (0.0); +} +vec4 texture2DProjLod (sampler2D sampler, vec3 coord, float lod) { + return texture2DLod (sampler, vec2 (coord.s / coord.p, coord.t / coord.p), lod); +} +vec4 texture2DProjLod (sampler2D sampler, vec4 coord, float lod) { + return texture2DLod (sampler, vec2 (coord.s / coord.q, coord.t / coord.q), lod); +} + +// +// Use the texture coordinate coord to do a texture lookup in the 3D texture currently bound +// to sampler. For the projective (�Proj�) versions, the texture coordinate is divided by coord.q. +// +// XXX +vec4 texture3DLod (sampler3D sampler, vec3 coord, float lod) { + return vec4 (0.0); +} +vec4 texture3DProjLod (sampler3D sampler, vec4 coord, float lod) { + return texture3DLod (sampler, vec3 (coord.s / coord.q, coord.t / coord.q, coord.s / coord.q), + lod); +} + +// +// Use the texture coordinate coord to do a texture lookup in the cube map texture currently bound +// to sampler. The direction of coord is used to select which face to do a 2-dimensional texture +// lookup in, as described in section 3.8.6 in version 1.4 of the OpenGL specification. +// +// XXX +vec4 textureCubeLod (samplerCube sampler, vec3 coord, float lod) { + return vec4 (0.0); +} + +// +// Use texture coordinate coord to do a depth comparison lookup on the depth texture bound +// to sampler, as described in section 3.8.14 of version 1.4 of the OpenGL specification. The 3rd +// component of coord (coord.p) is used as the R value. The texture bound to sampler must be a +// depth texture, or results are undefined. For the projective (�Proj�) version of each built-in, +// the texture coordinate is divide by coord.q, giving a depth value R of coord.p/coord.q. The +// second component of coord is ignored for the �1D� variants. +// +// XXX +vec4 shadow1DLod (sampler1DShadow sampler, vec3 coord, float lod) { + return vec4 (0.0); +} +// XXX +vec4 shadow2DLod (sampler2DShadow sampler, vec3 coord, float lod) { + return vec4 (0.0); +} +vec4 shadow1DProjLod(sampler1DShadow sampler, vec4 coord, float lod) { + return shadow1DLod (sampler, vec3 (coord.s / coord.q, 0.0, coord.p / coord.q), lod); +} +vec4 shadow2DProjLod(sampler2DShadow sampler, vec4 coord, float lod) { + return shadow2DLod (sampler, vec3 (coord.s / coord.q, coord.t / coord.q, coord.p / coord.q), + lod); +} + |