mojoshader_metal.c
author Caleb Cornett <caleb.cornett@outlook.com>
Tue, 07 Jul 2020 19:25:47 -0400
changeset 1279 b1f51cfa8933
parent 1252 ed07dd994125
permissions -rw-r--r--
Metal uniform buffer overhaul. 1. Metal now uses a single, ~1MB uniform buffer per frame that is shared among all shaders. From my testing this should be more than enough room for the FNA catalog (aside from possibly Little Racers Street with its memory leak). This is a major boon for Metal memory management since it only requires one buffer instead of 3,000 (in LRS's case)! And it simplifies the internal workings of mojoshader_metal dramatically. 2. Metal now has a MOJOSHADER_mtlMakeContextCurrent API to match GL and Vulkan. Other parts of the context API have been rewritten as well to match the behavior you'd expect. 3. The MOJOSHADER_mtlGetUniformBuffers function has been replaced with MOJOSHADER_mtlGetUniformData. Now that we only use a single uniform buffer, there's no need to return one for each of the shaders. 4. The MOJOSHADER_mtlGetFunctionHandle function no longer allocates memory. Instead, all MTLFunction handles are cached in the MOJOSHADER_mtlShader structs at library creation time. This removes the burden of memory management from the user. 5. A variety of formatting and documentation updates.

/**
 * MojoShader; generate shader programs from bytecode of compiled
 *  Direct3D shaders.
 *
 * Please see the file LICENSE.txt in the source's root directory.
 *
 *  This file written by Ryan C. Gordon.
 */

#define __MOJOSHADER_INTERNAL__ 1
#include "mojoshader_internal.h"

#if (defined(__APPLE__) && defined(__MACH__))
#define PLATFORM_APPLE 1
#endif /* (defined(__APPLE__) && defined(__MACH__)) */

typedef struct MOJOSHADER_mtlShader
{
    const MOJOSHADER_parseData *parseData;
    uint32 refcount;
    void *handle; // MTLFunction*
} MOJOSHADER_mtlShader;

// profile-specific implementations...

#if SUPPORT_PROFILE_METAL && PLATFORM_APPLE
#ifdef MOJOSHADER_EFFECT_SUPPORT

#include "TargetConditionals.h"
#include <objc/message.h>
#define msg     ((void* (*)(void*, void*))objc_msgSend)
#define msg_s   ((void* (*)(void*, void*, const char*))objc_msgSend)
#define msg_p   ((void* (*)(void*, void*, void*))objc_msgSend)
#define msg_uu  ((void* (*)(void*, void*, uint64, uint64))objc_msgSend)
#define msg_ppp ((void* (*)(void*, void*, void*, void*, void*))objc_msgSend)

// Error state...
static char error_buffer[1024] = { '\0' };

static void set_error(const char *str)
{
    snprintf(error_buffer, sizeof (error_buffer), "%s", str);
} // set_error

static inline void out_of_memory(void)
{
    set_error("out of memory");
} // out_of_memory

// Max entries for each register file type...
#define MAX_REG_FILE_F 8192
#define MAX_REG_FILE_I 2047
#define MAX_REG_FILE_B 2047

typedef struct MOJOSHADER_mtlContext
{
    // Allocators...
    MOJOSHADER_malloc malloc_fn;
    MOJOSHADER_free free_fn;
    void *malloc_data;

    // The constant register files...
    // !!! FIXME: Man, it kills me how much memory this takes...
    // !!! FIXME:  ... make this dynamically allocated on demand.
    float vs_reg_file_f[MAX_REG_FILE_F * 4];
    int vs_reg_file_i[MAX_REG_FILE_I * 4];
    uint8 vs_reg_file_b[MAX_REG_FILE_B];
    float ps_reg_file_f[MAX_REG_FILE_F * 4];
    int ps_reg_file_i[MAX_REG_FILE_I * 4];
    uint8 ps_reg_file_b[MAX_REG_FILE_B];

    // Pointer to the active MTLDevice.
    void* device;

    // The uniform MTLBuffer shared between all shaders in the context.
    void *ubo;

    // The current offsets into the UBO, per shader.
    int vertexUniformOffset;
    int pixelUniformOffset;
    int totalUniformOffset;

    // The currently bound shaders.
    MOJOSHADER_mtlShader *vertexShader;
    MOJOSHADER_mtlShader *pixelShader;

    // Objective-C Selectors
    void* classNSString;
    void* selAlloc;
    void* selContents;
    void* selInitWithUTF8String;
    void* selLength;
    void* selLocalizedDescription;
    void* selNewBufferWithLength;
    void* selNewFunctionWithName;
    void* selNewLibraryWithSource;
    void* selRelease;
    void* selUTF8String;
} MOJOSHADER_mtlContext;

static MOJOSHADER_mtlContext *ctx = NULL;

/* Uniform buffer utilities */

static inline int next_highest_alignment(int n)
{
    #if TARGET_OS_IOS || TARGET_OS_TV || TARGET_OS_SIMULATOR
    int align = 16;
    #else
    // !!! FIXME: Will Apple Silicon Macs have a different minimum alignment?
    int align = 256;
    #endif

    return align * ((n + align - 1) / align);
} // next_highest_alignment

static void update_uniform_buffer(MOJOSHADER_mtlShader *shader)
{
    if (shader == NULL || shader->parseData->uniform_count == 0)
        return;

    float *regF; int *regI; uint8 *regB;
    if (shader->parseData->shader_type == MOJOSHADER_TYPE_VERTEX)
    {
        ctx->vertexUniformOffset = ctx->totalUniformOffset;
        regF = ctx->vs_reg_file_f;
        regI = ctx->vs_reg_file_i;
        regB = ctx->vs_reg_file_b;
    } // if
    else
    {
        ctx->pixelUniformOffset = ctx->totalUniformOffset;
        regF = ctx->ps_reg_file_f;
        regI = ctx->ps_reg_file_i;
        regB = ctx->ps_reg_file_b;
    } // else

    void *contents = msg(ctx->ubo, ctx->selContents) + ctx->totalUniformOffset;
    int offset = 0;
    for (int i = 0; i < shader->parseData->uniform_count; i++)
    {
        if (shader->parseData->uniforms[i].constant)
            continue;

        int idx = shader->parseData->uniforms[i].index;
        int arrayCount = shader->parseData->uniforms[i].array_count;

        void *src = NULL;
        int size = arrayCount ? arrayCount : 1;

        switch (shader->parseData->uniforms[i].type)
        {
            case MOJOSHADER_UNIFORM_FLOAT:
                src = &regF[4 * idx];
                size *= 16;
                break;

            case MOJOSHADER_UNIFORM_INT:
                src = &regI[4 * idx];
                size *= 16;
                break;

            case MOJOSHADER_UNIFORM_BOOL:
                src = &regB[idx];
                break;

            default:
                assert(0); // This should never happen.
                break;
        } // switch

        memcpy(contents + offset, src, size);
        offset += size;
    } // for

    ctx->totalUniformOffset = next_highest_alignment(ctx->totalUniformOffset + offset);
    if (ctx->totalUniformOffset >= (int) msg(ctx->ubo, ctx->selLength))
    {
        // !!! FIXME: Is there a better way to handle this?
        assert(0 && "Uniform data exceeded the size of the buffer!");
    } // if
} // update_uniform_buffer

/* Public API */

MOJOSHADER_mtlContext *MOJOSHADER_mtlCreateContext(void* mtlDevice,
                                    MOJOSHADER_malloc m, MOJOSHADER_free f,
                                    void *malloc_d)
{
    MOJOSHADER_mtlContext *retval = NULL;
    MOJOSHADER_mtlContext *current_ctx = ctx;
    int i;

    ctx = NULL;

    if (m == NULL) m = MOJOSHADER_internal_malloc;
    if (f == NULL) f = MOJOSHADER_internal_free;

    ctx = (MOJOSHADER_mtlContext *) m(sizeof (MOJOSHADER_mtlContext), malloc_d);
    if (ctx == NULL)
    {
        out_of_memory();
        goto init_fail;
    } // if

    memset(ctx, '\0', sizeof (MOJOSHADER_mtlContext));
    ctx->malloc_fn = m;
    ctx->free_fn = f;
    ctx->malloc_data = malloc_d;

    // Initialize the Metal state
    ctx->device = mtlDevice;

    // Grab references to Objective-C selectors
    ctx->classNSString = objc_getClass("NSString");
    ctx->selAlloc = sel_registerName("alloc");
    ctx->selContents = sel_registerName("contents");
    ctx->selInitWithUTF8String = sel_registerName("initWithUTF8String:");
    ctx->selLength = sel_registerName("length");
    ctx->selLocalizedDescription = sel_registerName("localizedDescription");
    ctx->selNewBufferWithLength = sel_registerName("newBufferWithLength:options:");
    ctx->selNewFunctionWithName = sel_registerName("newFunctionWithName:");
    ctx->selNewLibraryWithSource = sel_registerName("newLibraryWithSource:options:error:");
    ctx->selRelease = sel_registerName("release");
    ctx->selUTF8String = sel_registerName("UTF8String");

    // Create the uniform buffer
    ctx->ubo = msg_uu(mtlDevice, ctx->selNewBufferWithLength,
                      next_highest_alignment(1000000), 0);

    retval = ctx;
    ctx = current_ctx;
    return retval;

init_fail:
    if (ctx != NULL)
        f(ctx, malloc_d);
    ctx = current_ctx;
    return NULL;
} // MOJOSHADER_mtlCreateContext


void MOJOSHADER_mtlMakeContextCurrent(MOJOSHADER_mtlContext *_ctx)
{
    ctx = _ctx;
} // MOJOSHADER_mtlMakeContextCurrent


void *MOJOSHADER_mtlCompileLibrary(MOJOSHADER_effect *effect)
{
    MOJOSHADER_malloc m = ctx->malloc_fn;
    MOJOSHADER_free f = ctx->free_fn;
    void *d = ctx->malloc_data;

    int i, src_len, src_pos, output_len;
    char *shader_source, *ptr;
    const char *repl;
    MOJOSHADER_effectObject *object;
    MOJOSHADER_mtlShader *shader;
    void *retval, *compileError, *shader_source_ns, *fnname;

    // Count the number of shaders before allocating
    src_len = 0;
    for (i = 0; i < effect->object_count; i++)
    {
        object = &effect->objects[i];
        if (object->type == MOJOSHADER_SYMTYPE_PIXELSHADER
         || object->type == MOJOSHADER_SYMTYPE_VERTEXSHADER)
        {
            if (!object->shader.is_preshader)
            {
                shader = (MOJOSHADER_mtlShader*) object->shader.shader;
                src_len += shader->parseData->output_len;
            } // if
        } // if
    } // for

    // Allocate shader source buffer
    shader_source = (char *) m(src_len + 1, d);
    memset(shader_source, '\0', src_len + 1);
    src_pos = 0;

    // Copy all the source text into the buffer
    for (i = 0; i < effect->object_count; i++)
    {
        object = &effect->objects[i];
        if (object->type == MOJOSHADER_SYMTYPE_PIXELSHADER
         || object->type == MOJOSHADER_SYMTYPE_VERTEXSHADER)
        {
            if (!object->shader.is_preshader)
            {
                shader = (MOJOSHADER_mtlShader*) object->shader.shader;
                memcpy(&shader_source[src_pos], shader->parseData->output,
                                                shader->parseData->output_len);
                src_pos += shader->parseData->output_len;
            } // if
        } // if
    } // for

    // Handle texcoord0 -> point_coord conversion
    if (strstr(shader_source, "[[point_size]]"))
    {
        // !!! FIXME: This assumes all texcoord0 attributes in the effect are
        // !!! FIXME:  actually point coords! It ain't necessarily so! -caleb
        repl = "[[  point_coord  ]]";
        while ((ptr = strstr(shader_source, "[[user(texcoord0)]]")))
        {
            memcpy(ptr, repl, strlen(repl));

            // "float4" -> "float2"
            int spaces = 0;
            while (spaces < 2)
                if (*(ptr--) == ' ')
                    spaces++;
            memcpy(ptr, "2", sizeof(char));
        } // while
    } // if

    // Compile the source into a library
    compileError = NULL;
    shader_source_ns = msg_s(
        msg(ctx->classNSString, ctx->selAlloc),
        ctx->selInitWithUTF8String,
        shader_source
    );
    retval = msg_ppp(ctx->device, ctx->selNewLibraryWithSource,
                        shader_source_ns, NULL, &compileError);
    f(shader_source, d);
    msg(shader_source_ns, ctx->selRelease);

    if (retval == NULL)
    {
        compileError = msg(compileError, ctx->selLocalizedDescription);
        set_error((char*) msg(compileError, ctx->selUTF8String));
        return NULL;
    } // if

    // Run through the shaders again, getting the function handles
    for (i = 0; i < effect->object_count; i++)
    {
        object = &effect->objects[i];
        if (object->type == MOJOSHADER_SYMTYPE_PIXELSHADER
         || object->type == MOJOSHADER_SYMTYPE_VERTEXSHADER)
        {
            if (object->shader.is_preshader)
                continue;

            shader = (MOJOSHADER_mtlShader*) object->shader.shader;
            fnname = msg_s(
                msg(ctx->classNSString, ctx->selAlloc),
                ctx->selInitWithUTF8String,
                shader->parseData->mainfn
            );
            shader->handle = msg_p(
                retval,
                ctx->selNewFunctionWithName,
                fnname
            );
            msg(fnname, ctx->selRelease);
        } // if
    } // for

    return retval;
} // MOJOSHADER_mtlCompileLibrary


MOJOSHADER_mtlShader *MOJOSHADER_mtlCompileShader(const char *mainfn,
                                            const unsigned char *tokenbuf,
                                            const unsigned int bufsize,
                                            const MOJOSHADER_swizzle *swiz,
                                            const unsigned int swizcount,
                                            const MOJOSHADER_samplerMap *smap,
                                            const unsigned int smapcount)
{
    MOJOSHADER_malloc m = ctx->malloc_fn;
    MOJOSHADER_free f = ctx->free_fn;
    void *d = ctx->malloc_data;

    const MOJOSHADER_parseData *pd = MOJOSHADER_parse("metal", mainfn, tokenbuf,
                                                     bufsize, swiz, swizcount,
                                                     smap, smapcount, m, f, d);
    if (pd->error_count > 0)
    {
        // !!! FIXME: put multiple errors in the buffer? Don't use
        // !!! FIXME:  MOJOSHADER_mtlGetError() for this?
        set_error(pd->errors[0].error);
        goto compile_shader_fail;
    } // if

    MOJOSHADER_mtlShader *retval = (MOJOSHADER_mtlShader *) m(sizeof(MOJOSHADER_mtlShader), d);
    if (retval == NULL)
        goto compile_shader_fail;

    retval->parseData = pd;
    retval->refcount = 1;
    retval->handle = NULL; // populated by MOJOSHADER_mtlCompileLibrary

    return retval;

compile_shader_fail:
    MOJOSHADER_freeParseData(retval->parseData);
    f(retval, d);
    return NULL;
} // MOJOSHADER_mtlCompileShader


void MOJOSHADER_mtlShaderAddRef(MOJOSHADER_mtlShader *shader)
{
    if (shader != NULL)
        shader->refcount++;
} // MOJOSHADER_mtlShaderAddRef


const MOJOSHADER_parseData *MOJOSHADER_mtlGetShaderParseData(
                                                MOJOSHADER_mtlShader *shader)
{
    return (shader != NULL) ? shader->parseData : NULL;
} // MOJOSHADER_mtlGetParseData


void MOJOSHADER_mtlBindShaders(MOJOSHADER_mtlShader *vshader,
                               MOJOSHADER_mtlShader *pshader)
{
    // Use the last bound shaders in case of NULL
    if (vshader != NULL)
        ctx->vertexShader = vshader;

    if (pshader != NULL)
        ctx->pixelShader = pshader;
} // MOJOSHADER_mtlBindShaders


void MOJOSHADER_mtlGetBoundShaders(MOJOSHADER_mtlShader **vshader,
                                   MOJOSHADER_mtlShader **pshader)
{
    *vshader = ctx->vertexShader;
    *pshader = ctx->pixelShader;
} // MOJOSHADER_mtlGetBoundShaders


void MOJOSHADER_mtlMapUniformBufferMemory(float **vsf, int **vsi, unsigned char **vsb,
                                          float **psf, int **psi, unsigned char **psb)
{
    *vsf = ctx->vs_reg_file_f;
    *vsi = ctx->vs_reg_file_i;
    *vsb = ctx->vs_reg_file_b;
    *psf = ctx->ps_reg_file_f;
    *psi = ctx->ps_reg_file_i;
    *psb = ctx->ps_reg_file_b;
} // MOJOSHADER_mtlMapUniformBufferMemory


void MOJOSHADER_mtlUnmapUniformBufferMemory()
{
    /* This has nothing to do with unmapping memory
     * and everything to do with updating uniform
     * buffers with the latest parameter contents.
     */
    update_uniform_buffer(ctx->vertexShader);
    update_uniform_buffer(ctx->pixelShader);
} // MOJOSHADER_mtlUnmapUniformBufferMemory


void MOJOSHADER_mtlGetUniformData(void **buf, int *voff, int *poff)
{
    *buf = ctx->ubo;
    *voff = ctx->vertexUniformOffset;
    *poff = ctx->pixelUniformOffset;
} // MOJOSHADER_mtlGetUniformBuffers


void *MOJOSHADER_mtlGetFunctionHandle(MOJOSHADER_mtlShader *shader)
{
    if (shader == NULL)
        return NULL;

    return shader->handle;
} // MOJOSHADER_mtlGetFunctionHandle


void MOJOSHADER_mtlEndFrame()
{
    ctx->totalUniformOffset = 0;
    ctx->vertexUniformOffset = 0;
    ctx->pixelUniformOffset = 0;
} // MOJOSHADER_mtlEndFrame


int MOJOSHADER_mtlGetVertexAttribLocation(MOJOSHADER_mtlShader *vert,
                                          MOJOSHADER_usage usage, int index)
{
    if (vert == NULL)
        return -1;

    for (int i = 0; i < vert->parseData->attribute_count; i++)
    {
        if (vert->parseData->attributes[i].usage == usage &&
            vert->parseData->attributes[i].index == index)
        {
            return i;
        } // if
    } // for

    // failure, couldn't find requested attribute
    return -1;
} // MOJOSHADER_mtlGetVertexAttribLocation


const char *MOJOSHADER_mtlGetError(void)
{
    return error_buffer;
} // MOJOSHADER_mtlGetError


void MOJOSHADER_mtlDeleteLibrary(void *library)
{
    msg(library, ctx->selRelease);
} // MOJOSHADER_mtlDeleteLibrary


void MOJOSHADER_mtlDeleteShader(MOJOSHADER_mtlShader *shader)
{
    if (shader != NULL)
    {
        if (shader->refcount > 1)
            shader->refcount--;
        else
        {
            msg(shader->handle, ctx->selRelease);
            MOJOSHADER_freeParseData(shader->parseData);
            ctx->free_fn(shader, ctx->malloc_data);
        } // else
    } // if
} // MOJOSHADER_mtlDeleteShader


void MOJOSHADER_mtlDestroyContext(MOJOSHADER_mtlContext *_ctx)
{
    MOJOSHADER_mtlContext *current_ctx = ctx;
    ctx = _ctx;

    if (ctx->ubo != NULL)
        msg(ctx->ubo, ctx->selRelease);

    if (ctx != NULL)
        ctx->free_fn(ctx, ctx->malloc_data);
    ctx = ((current_ctx == _ctx) ? NULL : current_ctx);
} // MOJOSHADER_mtlDestroyContext

#endif /* MOJOSHADER_EFFECT_SUPPORT */
#endif /* SUPPORT_PROFILE_METAL && PLATFORM_APPLE */

// end of mojoshader_metal.c ...