365 */
366 #define MAX_FRACTIONS sun_java2d_pipe_BufferedPaints_MULTI_MAX_FRACTIONS
367 #define MAX_FRACTIONS_LARGE MAX_FRACTIONS
368 #define MAX_FRACTIONS_SMALL 4
369
370 /**
371 * The maximum number of gradient colors supported by all of the gradient
372 * fragment shaders. Note that this value must be a power of two, as it
373 * determines the size of the 1D texture created below. It also must be
374 * greater than or equal to MAX_FRACTIONS (there is no strict requirement
375 * that the two values be equal).
376 */
377 #define MAX_COLORS 16
378
379 /**
380 * The handle to the gradient color table texture object used by the shaders.
381 */
382 static GLuint multiGradientTexID = 0;
383
384 /**
385 * This is essentially a template of the shader source code that can be used
386 * for either LinearGradientPaint or RadialGradientPaint. It includes the
387 * structure and some variables that are common to each; the remaining
388 * code snippets (for CycleMethod, ColorSpaceType, and mask modulation)
389 * are filled in prior to compiling the shader at runtime depending on the
390 * paint parameters. See OGLPaints_CreateMultiGradProgram() for more details.
391 */
392 static const char *multiGradientShaderSource =
393 // gradient texture size (in texels)
394 "const int TEXTURE_SIZE = %d;"
395 // maximum number of fractions/colors supported by this shader
396 "const int MAX_FRACTIONS = %d;"
397 // size of a single texel
398 "const float FULL_TEXEL = (1.0 / float(TEXTURE_SIZE));"
399 // size of half of a single texel
400 "const float HALF_TEXEL = (FULL_TEXEL / 2.0);"
401 // texture containing the gradient colors
402 "uniform sampler1D colors;"
403 // array of gradient stops/fractions
404 "uniform float fractions[MAX_FRACTIONS];"
405 // array of scale factors (one for each interval)
406 "uniform float scaleFactors[MAX_FRACTIONS-1];"
407 // (placeholder for mask variable)
408 "%s"
409 // (placeholder for Linear/RadialGP-specific variables)
410 "%s"
411 ""
412 "void main(void)"
413 "{"
414 " float dist;"
415 // (placeholder for Linear/RadialGradientPaint-specific code)
416 " %s"
417 ""
418 " float tc;"
419 // (placeholder for CycleMethod-specific code)
420 " %s"
421 ""
422 // calculate interpolated color
423 " vec4 result = texture1D(colors, tc);"
424 ""
425 // (placeholder for ColorSpace conversion code)
426 " %s"
427 ""
428 // (placeholder for mask modulation code)
429 " %s"
430 ""
431 // modulate with gl_Color in order to apply extra alpha
432 " gl_FragColor = result * gl_Color;"
433 "}";
434
435 /**
436 * This code takes a "dist" value as input (as calculated earlier by the
437 * LGP/RGP-specific code) in the range [0,1] and produces a texture
438 * coordinate value "tc" that represents the position of the chosen color
439 * in the one-dimensional gradient texture (also in the range [0,1]).
440 *
441 * One naive way to implement this would be to iterate through the fractions
442 * to figure out in which interval "dist" falls, and then compute the
443 * relative distance between the two nearest stops. This approach would
444 * require an "if" check on every iteration, and it is best to avoid
445 * conditionals in fragment shaders for performance reasons. Also, one might
446 * be tempted to use a break statement to jump out of the loop once the
447 * interval was found, but break statements (and non-constant loop bounds)
448 * are not natively available on most graphics hardware today, so that is
449 * a non-starter.
450 *
451 * The more optimal approach used here avoids these issues entirely by using
452 * an accumulation function that is equivalent to the process described above.
453 * The scaleFactors array is pre-initialized at enable time as follows:
454 * scaleFactors[i] = 1.0 / (fractions[i+1] - fractions[i]);
455 *
459 * distance between fraction[i] and fraction[i+1]. If we are below the
460 * target interval, this value will be negative, so we clamp it to zero
461 * to avoid accumulating any value. If we are above the target interval,
462 * the value will be greater than one, so we clamp it to one. Upon exiting
463 * the loop, we will have accumulated zero or more 1.0's and a single
464 * fractional value. This accumulated value tells us the position of the
465 * fragment color in the one-dimensional gradient texture, i.e., the
466 * texcoord called "tc".
467 */
468 static const char *texCoordCalcCode =
469 "int i;"
470 "float relFraction = 0.0;"
471 "for (i = 0; i < MAX_FRACTIONS-1; i++) {"
472 " relFraction +="
473 " clamp((dist - fractions[i]) * scaleFactors[i], 0.0, 1.0);"
474 "}"
475 // we offset by half a texel so that we find the linearly interpolated
476 // color between the two texel centers of interest
477 "tc = HALF_TEXEL + (FULL_TEXEL * relFraction);";
478
479 /** Code for NO_CYCLE that gets plugged into the CycleMethod placeholder. */
480 static const char *noCycleCode =
481 "if (dist <= 0.0) {"
482 " tc = 0.0;"
483 "} else if (dist >= 1.0) {"
484 " tc = 1.0;"
485 "} else {"
486 // (placeholder for texcoord calculation)
487 " %s"
488 "}";
489
490 /** Code for REFLECT that gets plugged into the CycleMethod placeholder. */
491 static const char *reflectCode =
492 "dist = 1.0 - (abs(fract(dist * 0.5) - 0.5) * 2.0);"
493 // (placeholder for texcoord calculation)
494 "%s";
495
496 /** Code for REPEAT that gets plugged into the CycleMethod placeholder. */
497 static const char *repeatCode =
498 "dist = fract(dist);"
499 // (placeholder for texcoord calculation)
500 "%s";
501
502 static void
503 OGLPaints_InitMultiGradientTexture()
504 {
505 GLclampf priority = 1.0f;
506
507 J2dTraceLn(J2D_TRACE_INFO, "OGLPaints_InitMultiGradientTexture");
508
509 j2d_glGenTextures(1, &multiGradientTexID);
510 j2d_glBindTexture(GL_TEXTURE_1D, multiGradientTexID);
511 j2d_glPrioritizeTextures(1, &multiGradientTexID, &priority);
512 j2d_glTexParameteri(GL_TEXTURE_1D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
513 j2d_glTexParameteri(GL_TEXTURE_1D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
514 j2d_glTexParameteri(GL_TEXTURE_1D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
515 j2d_glTexImage1D(GL_TEXTURE_1D, 0,
516 GL_RGBA8, MAX_COLORS, 0,
517 GL_BGRA, GL_UNSIGNED_INT_8_8_8_8_REV, NULL);
518 }
519
520 /**
521 * Compiles and links the MultipleGradientPaint shader program. If
561 * because the useMask case already does access gl_TexCoord[1] and
562 * is therefore not affected by this driver bug.
563 */
564 const char *vendor = (const char *)j2d_glGetString(GL_VENDOR);
565 if (vendor != NULL && strncmp(vendor, "ATI", 3) == 0) {
566 maskCode = "dist = gl_TexCoord[0].s;";
567 }
568 }
569
570 if (IS_SET(MULTI_LINEAR_RGB)) {
571 /*
572 * This code converts a single pixel in linear RGB space back
573 * into sRGB (note: this code was adapted from the
574 * MultipleGradientPaintContext.convertLinearRGBtoSRGB() method).
575 */
576 colorSpaceCode =
577 "result.rgb = 1.055 * pow(result.rgb, vec3(0.416667)) - 0.055;";
578 }
579
580 if (cycleMethod == CYCLE_NONE) {
581 sprintf(cycleCode, noCycleCode, texCoordCalcCode);
582 } else if (cycleMethod == CYCLE_REFLECT) {
583 sprintf(cycleCode, reflectCode, texCoordCalcCode);
584 } else { // (cycleMethod == CYCLE_REPEAT)
585 sprintf(cycleCode, repeatCode, texCoordCalcCode);
586 }
587
588 // compose the final source code string from the various pieces
589 sprintf(finalSource, multiGradientShaderSource,
590 MAX_COLORS, maxFractions,
591 maskVars, paintVars, distCode,
592 cycleCode, colorSpaceCode, maskCode);
593
594 multiGradProgram = OGLContext_CreateFragmentProgram(finalSource);
595 if (multiGradProgram == 0) {
596 J2dRlsTraceLn(J2D_TRACE_ERROR,
597 "OGLPaints_CreateMultiGradProgram: error creating program");
598 return 0;
599 }
600
601 // "use" the program object temporarily so that we can set the uniforms
602 j2d_glUseProgramObjectARB(multiGradProgram);
603
604 // set the "uniform" texture unit bindings
605 if (IS_SET(MULTI_USE_MASK)) {
606 loc = j2d_glGetUniformLocationARB(multiGradProgram, "mask");
607 j2d_glUniform1iARB(loc, 0); // texture unit 0
608 loc = j2d_glGetUniformLocationARB(multiGradProgram, "colors");
609 j2d_glUniform1iARB(loc, 1); // texture unit 1
610 } else {
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365 */
366 #define MAX_FRACTIONS sun_java2d_pipe_BufferedPaints_MULTI_MAX_FRACTIONS
367 #define MAX_FRACTIONS_LARGE MAX_FRACTIONS
368 #define MAX_FRACTIONS_SMALL 4
369
370 /**
371 * The maximum number of gradient colors supported by all of the gradient
372 * fragment shaders. Note that this value must be a power of two, as it
373 * determines the size of the 1D texture created below. It also must be
374 * greater than or equal to MAX_FRACTIONS (there is no strict requirement
375 * that the two values be equal).
376 */
377 #define MAX_COLORS 16
378
379 /**
380 * The handle to the gradient color table texture object used by the shaders.
381 */
382 static GLuint multiGradientTexID = 0;
383
384 /**
385 * This code takes a "dist" value as input (as calculated earlier by the
386 * LGP/RGP-specific code) in the range [0,1] and produces a texture
387 * coordinate value "tc" that represents the position of the chosen color
388 * in the one-dimensional gradient texture (also in the range [0,1]).
389 *
390 * One naive way to implement this would be to iterate through the fractions
391 * to figure out in which interval "dist" falls, and then compute the
392 * relative distance between the two nearest stops. This approach would
393 * require an "if" check on every iteration, and it is best to avoid
394 * conditionals in fragment shaders for performance reasons. Also, one might
395 * be tempted to use a break statement to jump out of the loop once the
396 * interval was found, but break statements (and non-constant loop bounds)
397 * are not natively available on most graphics hardware today, so that is
398 * a non-starter.
399 *
400 * The more optimal approach used here avoids these issues entirely by using
401 * an accumulation function that is equivalent to the process described above.
402 * The scaleFactors array is pre-initialized at enable time as follows:
403 * scaleFactors[i] = 1.0 / (fractions[i+1] - fractions[i]);
404 *
408 * distance between fraction[i] and fraction[i+1]. If we are below the
409 * target interval, this value will be negative, so we clamp it to zero
410 * to avoid accumulating any value. If we are above the target interval,
411 * the value will be greater than one, so we clamp it to one. Upon exiting
412 * the loop, we will have accumulated zero or more 1.0's and a single
413 * fractional value. This accumulated value tells us the position of the
414 * fragment color in the one-dimensional gradient texture, i.e., the
415 * texcoord called "tc".
416 */
417 static const char *texCoordCalcCode =
418 "int i;"
419 "float relFraction = 0.0;"
420 "for (i = 0; i < MAX_FRACTIONS-1; i++) {"
421 " relFraction +="
422 " clamp((dist - fractions[i]) * scaleFactors[i], 0.0, 1.0);"
423 "}"
424 // we offset by half a texel so that we find the linearly interpolated
425 // color between the two texel centers of interest
426 "tc = HALF_TEXEL + (FULL_TEXEL * relFraction);";
427
428 static void
429 OGLPaints_InitMultiGradientTexture()
430 {
431 GLclampf priority = 1.0f;
432
433 J2dTraceLn(J2D_TRACE_INFO, "OGLPaints_InitMultiGradientTexture");
434
435 j2d_glGenTextures(1, &multiGradientTexID);
436 j2d_glBindTexture(GL_TEXTURE_1D, multiGradientTexID);
437 j2d_glPrioritizeTextures(1, &multiGradientTexID, &priority);
438 j2d_glTexParameteri(GL_TEXTURE_1D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
439 j2d_glTexParameteri(GL_TEXTURE_1D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
440 j2d_glTexParameteri(GL_TEXTURE_1D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
441 j2d_glTexImage1D(GL_TEXTURE_1D, 0,
442 GL_RGBA8, MAX_COLORS, 0,
443 GL_BGRA, GL_UNSIGNED_INT_8_8_8_8_REV, NULL);
444 }
445
446 /**
447 * Compiles and links the MultipleGradientPaint shader program. If
487 * because the useMask case already does access gl_TexCoord[1] and
488 * is therefore not affected by this driver bug.
489 */
490 const char *vendor = (const char *)j2d_glGetString(GL_VENDOR);
491 if (vendor != NULL && strncmp(vendor, "ATI", 3) == 0) {
492 maskCode = "dist = gl_TexCoord[0].s;";
493 }
494 }
495
496 if (IS_SET(MULTI_LINEAR_RGB)) {
497 /*
498 * This code converts a single pixel in linear RGB space back
499 * into sRGB (note: this code was adapted from the
500 * MultipleGradientPaintContext.convertLinearRGBtoSRGB() method).
501 */
502 colorSpaceCode =
503 "result.rgb = 1.055 * pow(result.rgb, vec3(0.416667)) - 0.055;";
504 }
505
506 if (cycleMethod == CYCLE_NONE) {
507 sprintf(cycleCode,
508 /** Code for NO_CYCLE that gets plugged into the CycleMethod placeholder. */
509 "if (dist <= 0.0) {"
510 " tc = 0.0;"
511 "} else if (dist >= 1.0) {"
512 " tc = 1.0;"
513 "} else {"
514 // (placeholder for texcoord calculation)
515 " %s", texCoordCalcCode);
516 } else if (cycleMethod == CYCLE_REFLECT) {
517 sprintf(cycleCode,
518 /** Code for REFLECT that gets plugged into the CycleMethod placeholder. */
519 "dist = 1.0 - (abs(fract(dist * 0.5) - 0.5) * 2.0);"
520 // (placeholder for texcoord calculation)
521 "%s", texCoordCalcCode);
522 } else { // (cycleMethod == CYCLE_REPEAT)
523 sprintf(cycleCode,
524 /** Code for REPEAT that gets plugged into the CycleMethod placeholder. */
525 "dist = fract(dist);"
526 // (placeholder for texcoord calculation)
527 "%s", texCoordCalcCode);
528 }
529
530 // compose the final source code string from the various pieces
531 sprintf(finalSource,
532 /**
533 * This is essentially a template of the shader source code that can be used
534 * for either LinearGradientPaint or RadialGradientPaint. It includes the
535 * structure and some variables that are common to each; the remaining
536 * code snippets (for CycleMethod, ColorSpaceType, and mask modulation)
537 * are filled in prior to compiling the shader at runtime depending on the
538 * paint parameters. See OGLPaints_CreateMultiGradProgram() for more details.
539 */
540 // gradient texture size (in texels)
541 "const int TEXTURE_SIZE = %d;"
542 // maximum number of fractions/colors supported by this shader
543 "const int MAX_FRACTIONS = %d;"
544 // size of a single texel
545 "const float FULL_TEXEL = (1.0 / float(TEXTURE_SIZE));"
546 // size of half of a single texel
547 "const float HALF_TEXEL = (FULL_TEXEL / 2.0);"
548 // texture containing the gradient colors
549 "uniform sampler1D colors;"
550 // array of gradient stops/fractions
551 "uniform float fractions[MAX_FRACTIONS];"
552 // array of scale factors (one for each interval)
553 "uniform float scaleFactors[MAX_FRACTIONS-1];"
554 // (placeholder for mask variable)
555 "%s"
556 // (placeholder for Linear/RadialGP-specific variables)
557 "%s"
558 ""
559 "void main(void)"
560 "{"
561 " float dist;"
562 // (placeholder for Linear/RadialGradientPaint-specific code)
563 " %s"
564 ""
565 " float tc;"
566 // (placeholder for CycleMethod-specific code)
567 " %s"
568 ""
569 // calculate interpolated color
570 " vec4 result = texture1D(colors, tc);"
571 ""
572 // (placeholder for ColorSpace conversion code)
573 " %s"
574 ""
575 // (placeholder for mask modulation code)
576 " %s"
577 ""
578 // modulate with gl_Color in order to apply extra alpha
579 " gl_FragColor = result * gl_Color;"
580 "}", MAX_COLORS, maxFractions,
581 maskVars, paintVars, distCode,
582 cycleCode, colorSpaceCode, maskCode);
583
584 multiGradProgram = OGLContext_CreateFragmentProgram(finalSource);
585 if (multiGradProgram == 0) {
586 J2dRlsTraceLn(J2D_TRACE_ERROR,
587 "OGLPaints_CreateMultiGradProgram: error creating program");
588 return 0;
589 }
590
591 // "use" the program object temporarily so that we can set the uniforms
592 j2d_glUseProgramObjectARB(multiGradProgram);
593
594 // set the "uniform" texture unit bindings
595 if (IS_SET(MULTI_USE_MASK)) {
596 loc = j2d_glGetUniformLocationARB(multiGradProgram, "mask");
597 j2d_glUniform1iARB(loc, 0); // texture unit 0
598 loc = j2d_glGetUniformLocationARB(multiGradProgram, "colors");
599 j2d_glUniform1iARB(loc, 1); // texture unit 1
600 } else {
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