The Program3D class represents a pair of rendering programs (also called "shaders") uploaded to the rendering context.
Programs managed by a Program3D object control the entire rendering of triangles during a Context3D drawTriangles() call. Upload the binary bytecode to the rendering context using the upload method. (Once uploaded, the program in the original byte array is no longer referenced; changing or discarding the source byte array does not change the program.)
Programs always consist of two linked parts: A vertex and a fragment program.
- The vertex program operates on data defined in VertexBuffer3D objects and is responsible for projecting vertices into clip space and passing any required vertex data, such as color, to the fragment shader.
- The fragment shader operates on the attributes passed to it by the vertex program and produces a color for every rasterized fragment of a triangle, resulting in pixel colors. Note that fragment programs have several names in 3D programming literature, including fragment shader and pixel shader.
Designate which program pair to use for subsequent rendering operations by passing the
corresponding Program3D instance to the Context3D
You cannot create a Program3D object directly; use the Context3D
Frees all resources associated with this object. After disposing a
Program3D object, calling
upload() and rendering using this object will fail.
Uploads a pair of rendering programs expressed in AGAL (Adobe Graphics Assembly Language) bytecode.
Program bytecode can be created using the Pixel Bender 3D offline tools. It can also be created dynamically. The AGALMiniAssembler class is a utility class that compiles AGAL assembly language programs to AGAL bytecode. The class is not part of the runtime. When you upload the shader programs, the bytecode is compiled into the native shader language for the current device (for example, OpenGL or Direct3D). The runtime validates the bytecode on upload.
The programs run whenever the Context3D
drawTriangles() method is invoked. The
vertex program is executed once for each vertex in the list of triangles to be
drawn. The fragment program is executed once for each pixel on a triangle surface.
The "variables" used by a shader program are called registers. The following registers are defined:
|Name||Number per Fragment program||Number per Vertex program||Purpose|
|Attribute||n/a||8||Vertex shader input; read from a vertex buffer specified using |
|Constant||28||128||Shader input; set using the |
|Temporary||8||8||Temporary register for computation, not accessible outside program.|
|Output||1||1||Shader output: in a vertex program, the output is the clipspace position; in a fragment program, the output is a color.|
|Varying||8||8||Transfer interpolated data between vertex and fragment shaders. The varying registers from the vertex program are applied as input to the fragment program. Values are interpolated according to the distance from the triangle vertices.|
|Sampler||8||n/a||Fragment shader input; read from a texture specified using |
A vertex program receives input from two sources: vertex buffers and constant
registers. Specify which vertex data to use for a particular vertex attribute
register using the Context3D
setVertexBufferAt() method. You can define up to
eight input registers for vertex attributes. The vertex attribute values are read
from the vertex buffer for each vertex in the triangle list and placed in the
attribute register. Specify constant registers using the Context3D
methods. Constant registers retain the same value for every vertex in the
triangle list. (You can only modify the constant values between calls to
The vertex program is responsible for projecting the triangle vertices into clip space (the canonical viewing area within ±1 on the x and y axes and 0-1 on the z axis) and placing the transformed coordinates in its output register. (Typically, the appropriate projection matrix is provided to the shader in a set of constant registers.) The vertex program must also copy any vertex attributes or computed values needed by the fragment program to a special set of variables called varying registers. When a fragment shader runs, the value supplied in a varying register is linearly interpolated according to the distance of the current fragment from each triangle vertex.
A fragment program receives input from the varying registers and from a separate
set of constant registers (set with
setProgramConstantsFromVector()). You can also read texture data from textures
uploaded to the rendering context using sampler registers. Specify which texture
to access with a particular sampler register using the Context3D
method. The fragment program is responsible for setting its output register to a
AGAL bytecode for the Vertex program. The ByteArray object must use the little endian format.
AGAL bytecode for the Fragment program. The ByteArray object must use the little endian format.
Null Pointer Error: if vertexProgram or fragmentProgram is
Object Disposed: if the Program3D object was disposed either
directly by a call to
Agal Program Too Small: when either program code array is smaller than 31 bytes length. This is the size of the shader bytecode of a one-instruction program.
Program Must Be Little Endian: if either of the program byte code arrays is not little endian.
Native Shader Compilation Failed: if the output of the AGAL translator is not a compilable native shader language program. This error is only thrown in release players.
Native Shader Compilation Failed OpenGL: if the output of the AGAL translator is not a compilable OpengGL shader language program, and includes compilation diagnostics. This error is only thrown in debug players.
Native Shader Compilation Failed D3D9: if the output of the AGAL translator is not a compilable Direct3D shader language program, and includes compilation diagnostics. This error is only thrown in debug players. The following errors are thrown when the AGAL bytecode validation fails:
Not An Agal Program: if the header "magic byte" is wrong. The first byte of the bytecode must be 0xa0. This error can indicate that the byte array is set to the wrong endian order.
Bad Agal Version: if the AGAL version is not supported by the current SWF version. The AGAL version must be set to 1 for SWF version 13.
Bad Agal Program Type: if the AGAL program type identifier is not valid. The third byte in the byte code must be 0xa1. This error can indicates that the byte array is set to the wrong endian order.
Bad Agal Shader Type: if the shader type code is not either fragment or vertex (1 or 0).
Invalid Agal Opcode Out Of Range: if an invalid opcode is encountered in the token stream.
Invalid Agal Opcode Not Implemented: if an invalid opcode is encountered in the token stream.
Agal Opcode Only Allowed In Fragment Program: if an opcode is encountered in the token stream of the vertex program that is only allowed in fragment programs, such as KIL or TEX.
Bad Agal Source Operands: if both source operands are constant registers. You must compute the result outside the shader program and pass it in using a single constant register.
Both Operands Are Indirect Reads: if both operands are indirect reads.
Opcode Destination Must Be All Zero: if a token with an opcode (such as KIL) that has no destination sets a non-zero value for the destination register.
Opcode Destination Must Use Mask: if an opcode that produces only a 3 component result is used without masking.
Too Many Tokens: if there are too many tokens (more than 200) in an AGAL program.
Fragment Shader Type: if the fragment program type (byte 6 of fragmentProgram parameter) is not set to 1.
Vertex Shader Type: if the vertex program type (byte 6 of vertexProgram parameter) is not set to 0.
Varying Read But Not Written To: if the fragment shader reads a varying register that was never written to by the vertex shader.
Varying Partial Write: if a varying register is only partially written to. All components of a varying register must be written to.
Fragment Write All Components: if a fragment color output is only partially written to. All four components of the color output must be written to.
Vertex Write All Components: if a vertex clip space output is only partially written to. All components of the vertex clip space output must be written to.
Unused Operand: if an unused operand in a token is not set to all zero.
Sampler Register Only In Fragment: if a texture sampler register is used in a vertex program.
Sampler Register Second Operand: if a sampler register is used as a destination or first operand of an AGAL token.
Indirect Only Allowed In Vertex: if indirect addressing is used in a fragment program.
Indirect Only Into Constant Registers: if indirect addressing is used on a non-constant register.
Indirect Source Type: if the indirect source type is not attribute, constant or temporary register.
Indirect Addressing Fields Must Be Zero: if not all indirect addressing fields are zero for direct addressing.
Varying Registers Only Read In Fragment: if a varying register is read in a vertex program. Varying registers can only be written in vertex programs and read in fragment programs.
Attribute Registers Only Read In Vertex: if an attribute registers is read in a fragment program. Attribute registers can only be read in vertex programs.
Can Not Read Output Register: if an output (position or color) register is read. Output registers can only be written to, not read.
Temp Register Read Without Write: if a temporary register is read without being written to earlier.
Temp Register Component Read Without Write: if a specific temporary register component is read without being written to earlier.
Sampler Register Cannot Be Written To: if a sampler register is written to. Sampler registers can only be read, not written to.
Varying Registers Write: if a varying register is written to in a fragment program. Varying registers can only be written in vertex programs and read in fragment programs.
Attribute Register Cannot Be Written To: if an attribute register is written to. Attribute registers are read-only.
Constant Register Cannot Be Written To: if a constant register is written to inside a shader program.
Destination Writemask Is Zero: if a destination writemask is zero. All components of an output register must be set.
AGAL Reserved Bits Should Be Zero: if any reserved bits in a token are not zero. This indicates an error in creating the bytecode (or malformed bytecode).
Unknown Register Type: if an invalid register type index is used.
Sampler Register Out Of Bounds: if an invalid sampler register index is used.
Varying Register Out Of Bounds: if an invalid varying register index is used.
Attribute Register Out Of Bounds: if an invalid attribute register index is used.
Constant Register Out Of Bounds: if an invalid constant register index is used.
Output Register Out Of Bounds: if an invalid output register index is used.
Temporary Register Out Of Bounds: if an invalid temporary register index is used.
Cube Map Sampler Must Use Clamp: if a cube map sampler does not set the wrap mode to clamp.
Unknown Sampler Dimension: if a sample uses an unknown sampler dimension. (Only 2D and cube textures are supported.)
Unknown Filter Mode: if a sampler uses an unknown filter mode. (Only nearest neighbor and linear filtering are supported.)
Unknown Mipmap Mode: if a sampler uses an unknown mipmap mode. (Only none, nearest neighbor, and linear mipmap modes are supported.)
Unknown Wrapping Mode if a sampler uses an unknown wrapping mode. (Only clamp and repeat wrapping modes are supported.)
Unknown Special Flag: if a sampler uses an unknown special flag.
Output Color Not Maskable: You cannot mask the color output register in a fragment program. All components of the color register must be set.
Second Operand Must Be Sampler Register: The AGAL tex opcode must have a sampler as the second source operand.
Indirect Not Allowed: indirect addressing used where not allowed.
Swizzle Must Be Scalar: swizzling error.
Cant Swizzle 2nd Source: swizzling error.
Second Use Of Sampler Must Have Same Params: all samplers that access the same texture must use the same dimension, wrap, filter, special, and mipmap settings.
3768: The Stage3D API may not be used during background execution.
uploadSources (vertexSource:String, fragmentSource:String):Void